To add to this, Drew Curtis (founder of Fark.com) gave a talk on how he defeated a patent troll: http://www.ted.com/talks/drew_curtis_how_i_beat_a_patent_tro...

There are some good insights in this short talk, but there was also this comment by a user called Troll Busters:

This is unfortunate because Mr. Curtis was scammed. No, not by the patent troll, but by his lawyers who was more concerned about charging excessive fees when there was a much more cost-effective solution to his problem. The problem is not patent law but legal economics. This patent was easily invalidated by a simple and cost-efftive post-grant proceeding called a reexamination. However, law firms have been steering clients away from cost-effective proceedings in favor of much riskier and higher cost litigation to resolve disputes. Why? Because law firms need the high fees associated with patent litigation and discourage use of cost-effective post-grant proceedings to determine patent invalidity at the Patent Office.

I was familiar with the patent mentioned and proposed to wipe it out for $50K. We had the prior art needed to invalidate the patent. But each defendant's lawyer wanted to charge their clients fees and not give up the high-billing litigation legal work for such a simple solution that could have been shared collectively among the defendants. Instead, it allowed the troll to divide and conquer and force lucrative settlements for "nuisance fees" or the amount that would have to be paid to lawyers.

I don't know if the threat of a reexamination would have been enough to scare the patent troll away, but it would be very interesting if this were a viable method of nullifying the patent. I'm guessing it's not as easy as $50K-and-we're-done, else one of the victims in these cases would have attempted it already. But it seems like a successful invalidation would certainly kill the troll and save everyone the trouble and legal costs.

A former colleague of mine had information in his thesis which could invalidate a certain patent. For various unplanned reasons his thesis was not available online nor through his alma mater.

For a while, every year or two he would get a call from a lawyer who was willing to pay him a hefty fee for a copy of his thesis. For the lulz he always asked "do you want me to publish this somewhere?" and the lawyer always said "NO!"

I just watched the talk, and Troll Busters's comment is misplaced. Curtis didn't say exactly how much he spent defeating this troll, but it wasn't any $2M and probably not even $50k. He said he just asked for screenshots showing the alleged infringement, and the troll failed to provide any. When the troll pressed for settlement nonetheless, Curtis offered him zero, and the troll accepted. When the settlement agreement arrived, he crossed out the NDA provision, signed it, and sent it back. It was returned signed (to the surprise of Curtis's attorney). Curtis evidently did consult with his attorney a little, so it must have cost him something, but it didn't sound like it was very much.

In short this doesn't seem to have been a very determined or well-funded troll.

Troll Busters may have a point here, but it's clear that he/she/it is also trying to drum up business.

If you have good invalidating prior art, re-exam is cost effective and scary for the patentee. Not only can it knock out the patent, even a small change to the claim language in light of the prior art during re-exam means that the patentee can not collect damages prior to the modification. This affects the troll's current target and past and future licensees as well.

Even if you don't go into a reexam, it is a stick to wave to try to bring about a more reasonable settlement.