Biz Stone, co-founder of Twitter, Inc, speaks at Hult International Business School's Executive Speaker Series in San Francisco, CA on Tuesday, Oct. 16, 2012. (Ryan Anson/AP Images for Hult ... more 
Biz Stone, co-founder of Twitter, Inc, speaks at Hult International Business School's Executive Speaker Series in San Francisco, CA on Tuesday, Oct. 16, 2012. (Ryan Anson/AP Images for Hult International Business School) less 
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Associated Press
Wed, Oct 17, 2012 4:04 AM EDT