Yet another Twitter co-founder is leaving the company. In a blog post penned Tuesday, Biz Stone has said that he will be leaving Twitter to work on other projects.

Stone follows in the footsteps of fellow co-founder Ev Williams, who effectively left the company in March. Williams hinted at the possibility of coming up with a new venture at his Lake Tahoe retreat, and it looks like all that fresh air was good for him: he will be working with Stone now that Stone has decided to quit Twitter.

In his blog post, Stone explains that Twitter was something that he and fellow co-founders Williams and Jack Dorsey (who is currently Twitter’s chairman) put a lot of effort into, first under the umbrella corporation Obvious set up by Williams, and then as a growing entity on its own. Now, it seems, Stone is ready to hand over the reigns and begin working on other projects. However, he assures us that he won’t be completely out of Twitter’s reach, should the company need him:

“My work on Twitter has spanned more than half a decade and I will continue to work with the company for many years to come. During this time—especially lately, it has come to my attention that the Twitter crew and its leadership team have grown incredibly productive. 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.”

Stone will join Williams and another Obvious co-founder, Jason Goldman, to “develop new projects and work on solving big problems aligned along a simple mission statement: The Obvious Corporation develops systems that help people work together to improve the world.”