Hashcash is a nothing more than a neat trick involving a bit of Javascript that runs on the commenter's browser when they try to submit a comment. If they are running a web browser with javascript enabled (as nearly everyone is), they will just see a normal comment form and the comment will be accepted and displayed on the page immediately, the same as it was in the good old days before comment spam.

Lets compare hashcash to the alternatives:-

• Keyword blocking: this as ineffective in blogging as it was in the email world before it. It'll catch many spams, but it will also let many through. The blog owner has to keep looking through the spams and adding more and more keywords to the block list. Eventually you have to stop adding keywords or nobody will be able to add anything to the blog!
• IP blocking: this is ineffective as well because spamming is typically performed by zombie botnets (arrays of PCs that are infected with malware that follow the instructions of remote users while appearing to their owners to work normally). The spams appear from all manner of different IP addresses and besides, you still need to delete all the spams by hand with this method.
• CAPTCHAs - Completely Automated Public Turing Test to tell Computers and Humans Apart. These show the commenter an image that contains a string of letters and numbers. The user has to type this string input a field on the comment form along with their other details. There are two problems with CAPTCHAs. The first is that they are a usability nightmare - nobody likes having to pass a test like this every time they submit a form and for people with sight problems it can be impossible to pass. The second problem is that OCR (optical character recognition) techniques can used to defeat the test. As a result of 2, CAPTCHAs have been made progressively more and more difficult to pass, exacerbating problem 1.
• Bayesian filtering: This is the same as the most popular method of email filtering. A mathematical analysis is made to try and recognise if the comment looks like a spam in the same sort of way that we would recognise many spams as spam without even reading them - we recognise many different signs such as strings of garbage characters, implausible names and other features. This works about as well as it does with email spam, i.e. it produces some false positives (real comments tagged as spam) and false negatives (spams that get through).

As you can see from the above list, two of the four main alternative approaches are completely useless and the other two have serious problems of usability and effectiveness. Hashcash by comparison has been completely effective. That needs more emphasis really. In a year I have had less than 10 spam comments appear on my blog. That is few enough for me to believe that the spams that did get through were entered manually. That is something I can live with.

Akismet is a Bayesian filter system used by many bloggers including those on Wordpress. It uses a 'hive mind' approach that combines spam data from many users to improve effectiveness. Even so, lately I am seeing several bloggers (most notably Robert Scoble) complaining about Akismet either not filtering out all the spam, or catching too many genuine comments in it's filter. Apparently there is (or at least has been in the past) a Hashcash plugin for Wordpress. I would strongly suggest people check out this option. Akismet is a nice idea, but it is clearly not as effective as it should be. Hashcash is effective. I don't doubt that Scoble gets more attempts on his blog than I do on mine, but the results should scale because 100% effective scales.

The funny thing is though, when even you mention to Hashcash to bloggers, particularly those that are developers, they completely dismiss it. The main two complaints I hear are: (1) Spammers will eventually develop spam bots that can execute javascript and thus defeat hashcash; (2) It locks out people that aren't running Javascript in their browser, including those with disabilities that use text-only browsers.

I believe 2 isn't a major issue in that you can put a message on your comment form to the effect that if you are unable to use the form, please send an email and you'll add the comment for them. Maybe that will put some people off, but it shouldn't and it's certainly not deal-breaker for Hashcash. Besides, many people are now using conventional Javascript browsers with screen reader software instead of the old text mode browsers like Lynx, so this problem should diminish for disabled users. As for the tin-foil-hat-wearers that disable javascript in their browsers out of paranoia, they can stay silent for all I care :).

The final issue then is that spammers will someday build spambots that can defeat Hashcash. This is a completely bogus reason not to use Hashcash on your blog now. It is possible that one day hashcash will not be enoughto stop spambots. But at the moment the picture is far better for those using hashcash than it is for those relying on CAPTCHAs and Bayesian filtering. Make hay while the sun shines I say!

Before I talk about the player I eventually bought, the Samsung YP-Z5, let me explain why I didn't just buy an iPod Nano. If I just wanted to rip my own CDs and maybe play a few mp3 files I *ahem* collected from other places, the iPod would have been a fine choice. But ever since all-you-can-download subscription services have been available (like Napster, Rhapsody, etc.) I've been quite taken with the idea of being able to fill up the player with whatever music I want, all for a flat fee. Sadly, Apple has not seen the light on subscription services and their iTunes Store only supports pay-per-track downloads. Due to all the incompatabilities that DRM (Digital Rights Management) introduces, that means all Apple players are out of consideration. The other big player in DRM is Microsoft and the good thing about Microsoft's Windows Media DRM is that it is licenced to many manufacturers so you get a wide choice of players rather than being locked into those of one manufacturer (Apple). It has to be said that there are very few products as good as Apple's, but I believe the YP-Z5 is one of them.

The Samsung YP-Z5 is available in 1GB, 2GB and 4GB models, although there's so little price difference you'd be mad to buy anything but the 4GB model. The YP-Z5 is a bit thicker and heavier than the iPod Nano, but the reason is that it packs a much longer battery life (35 hours!) and a tough metal casing. I've heard it said that the iPod Nano is cursed by scratching of the case. Now the YP-Z5 is still going to get scratched since the front and back panels are pained (the sides are chromed), but it still feels like it can take quite a bit of abuse.

The control of the YP-Z5 was apparently designed by the same company that designed the first iPod "click wheel". However, to avoid patent/ design rights issues, the YP-Z5 uses a square touch-sensitive direction panel in the centre, with a ring of four buttons around the outside. The buttons all feel effective and should be reliable. The touch panel in the centre is, for my taste anyway, a bit fiddly. Because it's a direction pad, you don't slide your finger around it like with the click-wheel, you either repeatedly tap the up or down spot or hold your finger on it and wait for the auto-repeat (like a computer keyboard). This takes a bit of getting used to, but it's certainly masterable. Just be aware that if you lend your player to someone you might have to spend some time explaining it to them. The upside of the control difference to the iPod is that the YP-Z5 has a dedicated (metal!) volume control on the side of it. All my iPod owning friends have lemented the use of the click-wheel to control volume on the iPod - one stray press while adjusting volume and you can end up skipping tracks - very annoying.

As I mentioned at the top of the article, the Samsung YP-Z5 supports Microsoft's Pays For Sure(tm) initiative. This come along with Windows Media Player 10 and it's designed to make it easy for consumers to know which players are fully compatable with Windows Media 10. A lot of cheap, nasty MP3 players will play non-protected WMA files, but will not necessarilly play the tracks that you have paid to download. Fewer still are compatible with subscription based services like Napster To Go(tm) because they need to use a clock to enforce the "rental" model for downloaded files. Using my Napster To Go(tm) subscription is the only time I feel a little regret at buying a flash-memory based player instead of one containing a 30GB harddrive as even with 4GB of memory (enough for about 60 albums), you are always having to look at which albums to remove from the player so you can copy over your fresh downloads. I think people that pay for every single track they download have less of a problem here :)

When you've downloaded a ton of music to the YP-Z5 you'll want to play it. You can select music by Album, Artist or list all tracks at once. One thing you'll notice pretty quickly if you have downloaded MP3 files on your player is that the menu system relies entirely on meta-data (ID3 tags in MP3 files). You'll notice it because if you don't have the Artist or Album name set, or it's not set the same on all the tracks in the album, they'll appear in unexpected places. You also need the track number set in the ID3 data for the tracks to be listed in the right order and that is very rarely set in my experience. You might then have to spend some time 'cleaning up' the ID3 tags on your MP3 files before you download them to the YP-Z5. I'm told that it's pretty common for portable music players to work like this, but I really wish there was a "File System View" like you have with programs like winamp. I don't expect track numbers to be stored in the ID3 tags because I have "sort by filename" set and the files all have the track number at the beggining of their filename. Oh, and it's worth mentioning that with DRM protected files, you cannot change the meta-data, so if Napster (or whoever) have typed in the album name different on one track from the CD, you're out of luck - the only way you're going to get them to play in the right order is to make a custom playlist.

Talking of playlists, you can make them in Windows Media Player or Napster and download them to the player, but you cannot make them on the player itself. In fact that leads me to a wider point: This player is completely useless without a PC. Not only can you only charge it via the supplied USB cable, but there is no record function, you can't edit playlists or edit any of the file data on the player without a computer. Everything except actually playing music needs a PC with Windows Media 10 installed on it.

One major omission on the YP-Z5 in my opinion is the lack of any kind of sound equalizer. Sometimes you have to use headphones that aren't that great, or you just want a bit more bass on the track you're playing. It does have some things called DNSe effects, but these are like the cheesy sound effect modes you get on all music player apps - they muddy the sound or add superfluous echo/reverb and I don't understand why anyone would want to do that. There is also a "street mode", but as far as I can tell all that does is boost the volume some.

A few other things... The volume control is very wide ranging. I've read some user comments that say they think it is only adequate. All I can say is that they are either using very high impedance headphones, or they have hearing damage. I rarely get the volume above about 1/3rd of its range. On the headphone front, the YP-Z5 comes with some basic 'earbud' type earphones. They're not very comfortable, but if you can get them to seal in your ear, the sound is good, but like all earbuds, if they don't fill your ear canal, the bass will be very thin. Also on the accessory front, this player for reasons best known to Samsung, uses a proprietary connector on its lower edge. So if you lose or break the USB cable that comes with the player, you're really in trouble because the cable is needed even to charge the battery.

Conclusion

Priced at the same level as the iPod Nano, the Samsung YP-Z5 is the perfect alternative for those who want to use subscription music services. Also if you're only wanting to play your own CD rips, you might consider it instead of the iPod because of the much improved battery life and the greater robustness.

Since I bought my YP-Z5, Creative have made their own high-capacity flash-memory based player, the Creative Zen V. That has some extra features (built-in recording and the ability to play video), but it doesn't have such a good battery life and it's more 'plasticy'. Also, Apple have introduced a new version of the iPod Nano with up to 8Gb of memory and better battery life (although still I believe not as good as the YP-Z5). These will have to be considered, but I'm still very happy with my Samsung YP-Z5.

Personally, I think if this was anyone else leaving Microsoft, or Scoble leaving another other large company it wouldn't be nearly as big a deal. The anti-Microsoft mob are always going to look for some angle on how Microsoft's evil made it impossible for him to stay. The anti-blogging mob are going to look for some angle about how this means Microsoft doesn't really like staff bloggers after all. When it comes down to it, the company he's moving to is the perfect setup for Robert and if you had the chance to take the job that's perfect for you, you'd do it even if it meant taking a bit of flak in the meantime.

Scoble has been described as Microsoft's "Cheif humanising officer" and for sure, I feel better about Microsoft being a large group of people instead of the huge faceless corporation it seemed before. And I wasn't even in the anti-Microsoft mob to start with. Things have changed at Microsoft over the past few years and it's not all down to Scoble, but he does symbolise the changes that have occured in many departments. It used to be that if you found a bug in a product you'd have to go through support (if you had a support contract with them) or try emailing a general bug report address. You might get a response, you might not. You probably wouldn't get any communication from the people that actually developed the product that's for sure. Now you have developers blogging about what they're doing. They take feedback, some teams even give the great unwashed access to their bug tracking systems, and of course there are those crazy enough to appear on Channel 9 videos.

So good luck Robert. I hope it works out with the startup and it makes you rich! Microsoft will manage without you I feel and at least Channel 9 videos will no longer be punctuated by your manic laugh :)

Robert Scoble is famous for saying that if your marketing website doesn't have an RSS feed you should be fired. He's taken a lot of criticism for that stance and when I first read it I wasn't convinced it was that big a deal. However, I was recently compiling a list of Formula 1 team websites and was disappointed to find that only one of them had an RSS feed for it's news page. So I guess I'm now a believer.

For those not familiar with Formula 1 racing, there are currently 11 teams. All teams are required to design and manufacture their own cars (the engine may be bought in) to very high standards of both performance and safety. There are 18 races this year in North and South America, Europe, Asia and Oceania. Annual budgets range from $40M to $300M and staff levels from around 100 to over 1000. 6 of the 11 teams are owned by or closely allied to major motor car manufacturers. So this is a big global business - a long way from the likes of Champcar or IRL - and only the best will do for even the smallest of F1 operations. Even the manufacturer owned teams depend on external sponsorship and sponsors require maximum exposure in order to justify the money they hand over. That makes every chance to expose and promote their sponsors very important to the teams. So you'd think they would put a lot of effort into their web presence....

Well in a way they do. Almost all the sites are slickly produced by experienced web design agencies. Unfortunately these design agencies seem most intent on fulfilling a brief that was penned by someone who knows nothing about web usability or even good web marketing - as long as it looks pretty on this person's screen, they are happy.

The following is a table of woe. As you can see, only Renault have an RSS feed for the news section of their website. Many of the websites are all-flash affairs. Now I don't object to the use of flash on a website, but if the entire site is one big flash file it makes it impossible to bookmark pages, navigate using the standard back and forward buttons, or copy/paste from press releases etc. And that's without going into many of the accessability issues that web-standards fanatics like to go on about. Those sites that avoid the all-flash fate then have a chance to fail by using Frames is such a way as to make the bookmarking of individual pages almost impossible.

Renault F1 is the only team to come out with full marks - fittingly for the 2005 world champions! Williams, Midland F1, Toyota F1 and Honda are almost as good, they just need to add an RSS feed so fans can keep up with their news more easily. The rest should hang their heads in shame, sack their current web partners and start again.

[Note: Super Aguri F1 haven't really got a website yet - they're got their work cut out getting a car ready for the start of the season being the new boys for 2006 - so I'm not rating them yet.]

It's all PR hype though. We know the Cell is going to be the core of the Sony Playstaion 3 and there are possibly other applications for it in workstation accelerators. But don't expect to see it as widely used as IBM would like it to be. Firstly the Cell is not a cheap chip to manufacture. Some of the early hype made claims that by putting lots of simple processors together on one die they could make a very powerful chip at low cost compared to traditional solutions. This is just not the case though. The primary determiner in the manufacturing cost of chip is the die space it takes up and the Cell is as big as any high performance design. Even though the individual units of the Cell (SPE or Synergistic Processing Elements in IBM speak) are small and simple, when you jam 8 of them together (and add another true PowerPC processor to co-ordinate them) you end up with a big chip.

The other concern over the Cell is the ease of programming. Writing highly multi-threaded code is difficult anyway unless you have an easily seperable algorithm as your main computation task. But if you then take into account that the SPEs don't have access to main memory - only the 512KB they are bundled with - the whole business of co-ordinating data transfers to and from the SPEs adds an extra layer of complexity that any programmer would rather do without.

There is plenty of debate among game programmers over whether the PS3 offers as much useable processing power as the more conventional three-core PowerPC CPU in the Xbox 360 because the potention of the Cell will be so hard to realise. Being able to decode 48 MPEG2 streams simultaneously isn't that useful in most applications.

Because I read some prominent blogs written by people who blog more about blogging than anything else, I'm aware of a few sites that provide value added services to bloggers. One of them Technorati and another is Feedburner (other's I haven't delved into are del.ici.ous and memorandum).

Lets start with Technorati. As far as I can tell, this is mostly a search-engine for blogs. Rather than rely entirely on body text though, it allows you to provide extra information about both the blog itself and individual posts in the form of Tags. Tags are just words or short phrases really. There is no moderation or control on the use of tags either. There is nothing other than the cleverness of Technorati's search algorithms to stop you "tag stuffing" the same way people practiced "meta keyword stuffing" before Google came along and made it redundent. I'm not sure how much future there is in tagging, not just on Technorati, but also on Flickr, del.ici.ous or anywhere else. It seems to work well now because there are not so many users and those that are tagging are enthusiasts rather than lowlife search-optimizers.

Technorati also allows bloggers to "claim" their blog. That allows them to get more detailed information, provide a description and tags for the blog as a whole and add technorati-provided live data to their blogs. It took me a long time to 'claim' my blog due to some stupid javascript error on that part of the technorati website. I sent a support request in, but since you can only set the title to "I can't claim my blog" I guess it got burried under all the support requests from people who are too clueless to follow the instructions. This is a common 1st-line support error: Assuming all your users are equally stupid, thus failing to provide the ones who aren't good enough service. After 5 days the support request hasn't been answered. I still managed to claim my blogs after a couple of days of repeatedly trying though - god knows how, it seems pretty random.

The other service I wanted to mention is Feedburner. I hear it talked about a lot, possibly because I read Brad Feld's blog (he's a VC that's invested in Feedburner). The problem with Feedburner is working out what it does, or more to the point, how it does it. Their publishers page gives a list of services, some of which sound very useful (mostly the reader count), others I'm not so sure about. A lot of them didn't have explanations when I last looked but I note that most of them have an explanatory page now. Unfortunately most of the pages are written in the same talking to a suit who thinks they understand computers language as their About page (the "elevator pitch"). It talks about the serives they provide in only the vaguest terms before spilling the kind of information that only venture capitalists give a toss about - the names of the management team.

How about telling me how I'm going to implement all these wonderful services? I've thought about it long enough to realise that they probably have to slurp your RSS feed and then modify it and serve it from their own servers in order to do the things they claim. The problem with this is that I have to modify my blog code in order to point potential subscribers to Feedburner's copy of my feeds. Then if I stop using Feedburner, or god forbid, they fail to get further funding and cease operation, I lose all those subscribers. Plus all the subscribers I might currently have will need to somehow get shifted onto Feedburner's servers or they miss out of the FeedFlare and I mess out on the stats anaylsis. The thing is, this might not be the case, but I don't know because the only way for me to find out at present is to sign up for a Feedburner account and then read the implementation instructions. So I haven't bothered yet.

There is no web front-end to Napster so you have to install their software on your PC. Downloading is a breeze if you use Internet Explorer - FireFox users might have to put up with some errors before getting their download. Once downloaded, you install the software and then create an account. This involves entering your credit card details so that they can bill you the instant your trial period expires. I presume it also stops people repeatedly trailing the software for free.

Once you're up an running you'll discover an interface that's pretty similar to Apple iTunes. That's not at all surprising given the success of iTunes. You can spend the time ripping your CDs with the built in ripper or import any audio files you already have on your PC into the library. That didn't apply to me due to the HD disaster, so I went ahead and searched for music to listen to.

Slightly confusing at first is the fact that as a subscriber you can listen to also all the music in Napster's library without additional fees on your PC (and up to 2 others) and yet there are still links and buttons everywhere in the interface to 'buy' tracks and albums. This is because the subscription only allows you to listen to the music on your PC and compatible portable player if you paid the extra £5 a moth for that feature. If you want to burn CDs or retail access to a certain track once after you cancel your subscription, you need to 'buy' that track the same way you do with a non-subscription site like iTunes. I put the word 'buy' in quotes because the files are heavily DRM encumbered and you're really only buying a licence to use the music under certain restrictive circumstances. Still, if you want to make a compilation CD to put on at a party or something, you'll need to pay the 79p a track that Napster currently charge.

So lets assume that like me, you only really listen to music at your PC and you have broadband internet access. In this case you can stream the music off the Napster servers. This saves a lot of harddrive space, but it does mean that if your net connection drops, things go silent pretty quick as there is very little buffering. You can download the music to your harddrive if you don't have access to the net continuously. You'll still need to connect to Napster every so often though so the software can renew the "rental" of the files after confirming that your subscription is ongoing.

As well as being able to search for artists, albums and tracks, there are other ways to discover music. There are downloadable playlists, some just on a theme, others compiled by celebrities. Another advertised feature is "40+ advert free, interactive radio stations". This is one feature that doesn't work very well at the time I write this review. You see the "radio station" is really just a dynamic playlist - the music streams from their servers anyway so the only thing of interest is the choice of songs. Unfortunately the algorithms they use to pick the order of songs don't work very well. Most of the tracks on a given 'station' are picked by Napster staff - the order is randomised and a portion loaded into your playlist window. It's likely in any given try that you'll only get through the first twenty songs before you get a song you've already heard, even though there might be new songs further down the playlist. It has a facility to make a custom radio station based on a selection of tracks from your library. I didn't try this because my library is empty since there's no need for me to download tracks. This doesn't seem to be taken into account.

OK, I've got through all that without mentioning what is by far the biggest problem with Napster - the sound quality. They use WMA encoding which in itself is not a problem for me. The problem is that they encode their files at 128kbps. Even though WMA is more efficient than standard mp3, 128kbps is still vastly inadequate for most music. Subjective quality on the music I listen to varies from OK-ish (Scissor Sisters) to completely unlistenable (Green Day) due to the phasing in and out of high frequencies. This is such a shame because for me, the all-you-can-eat subscription model works, the price is right, but the audio quality, to be frank, sucks.

I'd rate Napster 6/10 at the current time due to the audio quality. It's the only major flaw but boy, is it a big one. If they increased the bitrate to 192kbps that would make most music listenable and then I've give the service 9/10. If they fixed the niggling bugs (many of which I've left out of this post for brevity but if you use Napster you'll be aware well aware of them) and increased filled in some of the obvious omissions in their library I could happily give the service 10/10.

I'd like to include some sound files to demonstrate how bad the audio quality is, but that would obviously be against the law (and their terms of service). If you want to try Napster yourself go to www.napster.com for USA residents and www.napster.co.uk for Brits. I don't think there's a referrer scheme unfortunately. A word of warning though - I'm still a subscriber (despite the flaws), but I've read on the built-in chat room boards that unsubscribing is a bit of a hassle.

I'd like to try Yahoo's service, but it's only available to US residents. I read Microsoft is setting up a Napster-alike that will presumably be available in Europe so I'll look forward to reviewing that at some point.