Twitter Inc. co-founders Biz Stone and Evan Williams said they are moving on from the microblogging service, media reports said Wednesday. “The Twitter crew and its leadership team have grown incredibly productive,” Stone said on the blog. “I’ve decided that the most effective use of my time is to get out of the way until I’m called upon to be of some specific use.” The two will continue to advise Twitter on strategic matters, but devote the lions\' share of their time to The Obvious Corporation, Stone said. Obvious was first created by Williams to buy back a company from investors that he and Stone failed to sell about six years ago, Stone said. The two began working together after leaving Google in 2005. The company will also be run by Jason Goldman, a former Twitter executive, Stone said.