What do you call it when...?

What do you call it when someone adds a comment to your post that purports to be genuine, but is really just a self serving gesture to get their own URL in there?

They'll say something vaguely complimentary, then something vaguely critical (to add a tone of verisimilitude) but generic, so they can add onto every post they think, for whatever reason, their own message or URL might have traction.

At first I thought parasite--dictionary.com: an organism that lives on or in an organism of another species, known as the host, from the body of which it obtains nutriment.

But then I thought maybe it was just marking--you know, the way a male dog lifts his leg on various things to add his scent, to proclaim his territory.

Maybe a little of both...