I know it is against the rules to advertise with links in your trades. But what about those that circumvent this restriction with their website as their name?

I once reported that, but he's still active. If that kind of advertising is allowed, what's to stop me from creating (lots of) Alt accounts, becoming a donor and then advertise my website with (hard to proof) fake trades? (not implying that that is the case below)

http://www.tf2outpost.com/user/163944
http://www.tf2outpost.com/user/255251
http://www.tf2outpost.com/user/121246 (although inactive for some time now)
(all from the same guy)
There are others, maybe less obvious, but the above are only an example.

Full disclosure: I had a rather ugly argument with the site owner at his blog a while back about his legitimacy, manners and double standards (but not started by me, imho).