dp619 writes "The tactic of patenting open source software to guard against patent trolls and the weaponization of corporate patent portfolios is gaining momentum in the FOSS community. Organizations including the Open Innovation Network, Google and Red Hat have built defensive patent portfolios (the latter two are defending their product lines). This approach has limitations. Penn State law professor Clark Asay writes in an Outercurve Foundation blog examining the trend, 'Patenting FOSS may help in some cases, but the nature of FOSS development itself may mean that patenting some collaboratively developed inventions is inherently more difficult, if not impossible, in many others. Consequently, strategies for mitigating patent risk that rely on FOSS communities patenting their technologies include inherent limitations. It's not entirely clear how best to reform patent law in order to better reconcile it with alternative models of innovation. But in the meantime, FOSS still presents certain advantages that, while dimmed by the prospect of patent suits, remain significant.'"