Now he mentions it, I've been seeing a lot of comments lately that are something like
"Nice info, thanks for sharing. Facebook developers"all in plain text. And the "signature" has often been something that's even less relevant than this.
I had been thinking that they were naive, and didn't know how to put links into comments, so was deleting them rather than marking as spam. Time to change the comments moderation policy, I think, down the spam-shute they go.