Co-Founder Biz Stone Is Leaving Twitter

LOS ANGELES (AP) — Isaac "Biz" Stone is moving on from Twitter, just five years after co-founding the microblogging site that has become integral to the social media scene around the globe.

Stone, 37, said Tuesday on his blog that he will work with the company "for many years to come," but that the most effective use of his time now is to "get out of the way" of Twitter's crew and leadership team until he's called upon to be of some specific use.

Stone says he plans to focus on helping schools, nonprofits and company advisory boards. He's also relaunching Obvious Corp. with fellow Twitter co-founder Evan Williams to develop new projects.

The move comes as Twitter has been trying to build upon its popularity to make more money by selling more ads. The privately held company doesn't disclose its finances, but research firm eMarketer Inc. estimates Twitter will bring in advertising revenue of about $150 million this year.