They produce a lot of bunk. Popular among the left, pseudo-intellectual and catering to an anti-Israel/anti-globalist crowd. Lots of footnotes from dubious sources. Very few effective solutions to the outrages alleged are ever outlined, the articles are mainly agit-prop in nature.
Sort of like what you would get if Noam Chomsky mated with Alex Jones.
One way to look at this is the off-chance that these sorts of sites are a deliberate conspiracy within a conspiracy. A way to send otherwise good people swirling around in a maelstrom of flotsam and jetsam. A neutralizer of action, a mis-direction campaign.