The Twitter duo are back! We're excited to announce that co-founders Biz Stone and Evan Williams are joining us on stage at Disrupt, after their widely publicized departure from leading Twitter to focus on social entrepreneurship. They'll be speaking about their stealthy social-good incubator, Obvious (which invests in companies such as the recently launched online conversation platform, Branch), and why technology founders can make a huge impact on the world while making money.

