Some of them are just mentally ill trolls, sitting in mommy's basement with nothing better to do.

But some of them are paid bashers, paid by pump'n'dump groups.

And some of them are IN the pump'n'dump groups. At one time on the AVXL board they were openly soliciting people to join their pump/dump groups. I wouldn't have believed it if I hadn't seen it (and also, gotten a PM from two different groups, inviting me to join). I'm not sure if I should be flattered or insulted that one of them said they liked my writing style.