maybe they're paying these idiots to put their ads in their signatures
>Paying.
In my experience over the years, I've come to learn that people that do this are either willing, or useful idiots.
They're actively spamming and damaging their own image in basically the one place that might have a reason to accept them among the flock, a forum dedicated to Bitcoins, mining and ETC.
They're not being paid to do this, I think pirate is behind the BFL/ASIC/AVALON Next-Gen miners, mark my words.