I think Fidel has commented on this before but this is the first time in a long while I've come across someone doing this.
Slashdot allows you to include a signature at the end of each post. Some people put witty quotes, some put adverts (such as the infamous 'click here for a free iPod'advert). Slashdot has a mechanism in place for people who don't want to see signatures, they can disable them.
Some sneaky twats get around this by placing their advert at the end of their comment by copying and pasting. Because the advert is now part of the comment, not the signature, it is still shown. Personally I add anyone doing this to my foes list because this is not better than spam. The way he words his comments is confusing as well. Since there's no dividing line between his genuine comment and the link, it's easy to just click his link thinking it's relevant to what he's saying when in fact it's just him whoring his blog.
Anyway, the lastest addition to my foes list is kidtux1.