Does Yahoo Facebook Patent War Threaten Startups?

So much for the free and open Internet. Remember back in March, when Yahoo sued Facebook for patent infringement, claiming ““Facebook’s entire social network model “is based on Yahoo!’s patented social networking technology.”

In response, Facebook in 1Q 2012 went out and purchased over $600 million in patents and filed a patent infringement counterclaim against Yahoo.

I wonder how many social media and other startups are subject to being crushed by these patent trolling giants? Will angels and venture capitalists require patent due dilligence?