Twitter Co-Founder Stone Joins Spark Capital

Twitter Inc. co-founder Biz Stone is joining venture firm Spark Capital as a strategic adviser, according to a blog posting from Spark partner Bijan Sabet.

“Biz will help us think through and evaluate new investment opportunities,” Sabet said in the posting. “Additionally he will provide us with valuable insight about our current portfolio companies.”

Stone, 37, announced last month that he was taking a further step back from Twitter along with fellow co-founder Evan Williams, so they could devote their time to Obvious Corp., a company aimed at incubating new ideas. Stone and Williams began working together after leaving Google Inc. (GOOG) in 2005, and developed a project that led to the formation of Twitter two years later.

Spark, a Boston-based firm founded in 2005, is an investor in Twitter and Sabet serves on the social-networking company’s board. Spark first took a stake in San Francisco-based Twitter in 2008 and participated in the next two financings the following year.

In addition to Twitter, Sabet led Spark’s investments in Web and mobile companies Tumblr Inc., Foursquare Labs Inc. and Boxee Inc.

Jack Dorsey, who co-founded Twitter with Stone and Williams, returned to an active role with the company this year. He is also chief executive officer of Square Inc., a mobile- payment company that he started in 2009.

To contact the reporter on this story: Ari Levy in San Francisco at

To contact the editor responsible for this story: Tom Giles at

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