I think its time that the internet as a whole weaponized agains the patent trolls.
We need a coalition of companies against software patents, where upon joining you declare never to pursue a software patent suit offensively, and pledge to donate all the relevant patents to any other member for defensive purposes.
I might not stop "pure trolls" that do absolutely nothing but sue others, but it would definitely stop companies like Yahoo that use their patent chest as a last stand during the downfall.