5) Independant patent license firms. I guess it is a possibility, but in the end, companies that mostly manufacture lawsuits usually go broke. Why would you sue a non-profit if you were mostly trying to make a buck with the lawsuit?
IANAL, but I think this category would be higher. For the simple reason that the non-profit might be viewed as low-hanging fruit and easy to pluck.
Remember, what some of these (a lot?) "patent license firms" (now that's a lot nicer than what I would have called them) try to do is get easy targets to license the patent. This makes it easier to get other companies to license the patent.
Often, the smaller targets will settle and license the patent because the cost to defend themselves is so high that it is cheaper to pay the license fees than to fight (this sounds familiar, oh yeah, protection rackets). These "firms" then use those licensees to legitimize their patent, claiming others licensing the patent "proves" their patent is enforceable. Then they target bigger and more lucrative fish.
[My jaded comments aside, I think there is a place for the US patent system to protect true invention and innovation. It's just been twisted into something -- well, I don't need to say it, you already know.]
