I got really sick of the comment spam on this site and realised that it was my responsibility as a web master to prevent it and thus ensure that only deserving sites had their sites boosted by links from this site. Akismet was, and remains, installed – but it wasn’t really cutting it. Although it has stopped an extraordinary 105,428 comments and trackbacks since installation. I’ve now implemented reCAPTCHA which means you have to type a couple of blurred words to make a comment. While this requires effort on the part of the user, which is a great shame, the good news is that your efforts do not go to waste. ReCAPTCHA uses one of the words you input to check you are human, the other helps to make electronic copies of scanned in books, a la Project Gutenberg.
Apologies for the inconvenience, blame the spammers!