In order to preserve what little sanity I have left I've changed the way comments are handled on here slightly.
Since comment and trackback spammers seem to target old posts I've decided to automatically close comments on posts that are 6 months old or older.
The old posts that were attracting the odd comment were mainly to do with older versions of Ubuntu etc., so there's not much point in accepting new comments since the software has changed in the last couple of years.
The other reason why I'm doing this is because I made a boo boo the other day and turned up the spam checking a little too high. This meant that I may have blocked several legitimate comments and had to spend a couple of hours trawling through about 20k+ worth of spam comments to rescue them.
I'll update the comment policy of the site shortly to reflect the new "regime"