By | October 10 2012 11:09 AM

With Jack Dorsey’s mobile payment startup Square quickly becoming one of Silicon Valley’s rising stars after a high-profile deal with Starbucks (Nasdaq: SBUX) helped attract renewed investor interest and raise the company to a $3.25 billion valuation, many began to wonder how much role, if any, co-founder Jack Dorsey was still playing in the other prominent tech startup he helped found: Twitter.