The most recent This American Life took on patent trolling. From the transcript:
Patents make it safe to share and to innovate. But today, lots of investors and innovators in Silicon Valley, maybe the majority, would tell you the patent system is doing the exact opposite of what it’s supposed to. It’s not promoting innovation. It’s stifling it. Because patent lawsuits are on the rise. Patent trolls are on the move. Patent lawsuits are so common now that it’s hard to find even one semi-successful startup in Silicon Valley that has not been hit with a suit, which slows innovation, makes it harder for companies to prosper, hurts our global competitiveness (is this getting big enough for you?), costs us all more money when we buy the stuff these companies sell.