Nope - I've never turned out my forum signature ("sig"), nor would I pay another to do such, for me/us. However, I do know many have done well selling theirs - that was their only "task" (somewhat of a P.Hilton life).

MHO, it is not much different from me holding a flashing mini-billboard, while conversing with my friends, or business acquaintances. Each time I ramble, I hold up some sign, ensuring all (friends & acquaintances) see & know what I am promoting, over and over and over and over and...

I'd rather use any of the many other marketing tactics to gain webmasters, such as increasing percentages.
Or I'll suck 'em in with my fabulous "fluffing"