Disappointing earnings revive speculation on Twitter's future

By Yasmeen Abutaleb SAN FRANCISCO (Reuters) - Twitter Inc disappointed investors yet again on Tuesday with second-quarter earnings that missed estimates and a lower-than-expected outlook, reviving chatter about a possible sale of the company and the future of Chief Executive Officer Jack Dorsey. With the stock falling almost 15 percent Wednesday, Twitter shares are down 50 percent since Dorsey returned last summer to the helm of the social media company he co-founded. At a market cap of about $1