Twitter co-founder Biz Stone to return to the struggling social-media service

Twitter co-founder Biz Stone said Tuesday that he is rejoining the company six years after he left, becoming the second creator to return to help revive the struggling social-media service.

Twitter co-founder Biz Stone said Tuesday that he is rejoining the company six years after he left, becoming the second creator to return to help revive the struggling social-media service.