Yammer CEO says he won’t hire anyone from Yahoo who doesn’t quit in next 60 days

David Sacks, the CEO of Yammer, is pissed. Last month he was hit with his first lawsuit from a patent troll. So when he saw that Yahoo was going after Facebook for patent infringement, he drew a line in the sand (well, on Twitter to be precise): “I’m declaring it: Yammer will never hire another former Yahoo employee who doesn’t leave in the next 60 days. Who will join me? #stopyahoo“

If Facebook pays up, experts say Yahoo may go full time patent troll

Yahoo has put the IP squeeze on Facebook, slapping it with a patent lawsuit during the quiet period in the run up to the social network’s IPO. While it’s tempting to see this as the first shot fired in a broader patent war centered around social networking, Lance Lieberman, a veteran New York patent lawyer with a specialty in software, thinks it’s just Yahoo’s first step down the dark path towards life as a patent troll.