Twitter Expat Dick Costolo at Work on Fitness Startup

CNBC: Six months after stepping down as Twitter CEO, Dick Costolo said he’s working on a fitness startup and is joining venture capital firm Index Ventures as partner. In a series of tweets, Costolo didn’t give details on what types of companies he’ll focus on at Index, just saying he’ll invest in entrepreneurs and work with existing portfolio companies. Costolo said he’s gotten to know the firm though a friend, partner Danny Rimer.