I'm pretty sure the penny stock newsletters act as promoters for penny stock companies in exchange for $$$ or stock options but I'm not exactly sure on the legality behind it all.
At 16 years old John Lebed was gaming penny stocks kind of like what these canadian guys were doing but he was gaming yahoo finance message boards. He got busted and he's now doing legit penny stock promotion. I think he's making a lot more with this than he did gaming the system.
So the legal opportunity for good marketers is out there in this niche, just got to do your legwork like anything else