Twitter: Make that almost San Francisco

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Twitter, the popular messaging site, may be growing out of its startup phase with a possible headquarters move to Brisbane, California, according to brokerage sources in the San Francisco Business Times.

The company appears to have more than 175 million users, has sent over 25 billion tweets, and 100 million accounts added in 2010, according to statistics from Royal Pingdom. What do these numbers have to do with moving headquarters? Twitter is growing and with more than 300 employees it may be looking for more room.

Twitter moved to its current location at 795 Folsom St., Suite 600 in San Francisco a little over a year ago and, according to the New York Times, it expanded from the sixth floor to the third floor in May. The article goes on to quote Twitter’s chief executive, Dick Costolo, as he predicted that Twitter will probably outgrow its 62,000 square feet around the spring of 2011 and need to take over new space in the building or move elsewhere.

The rumor is that the company may take over a 200,000 square feet complex on Sierra Point (pictured above) in Brisbane (just south of San Francisco).  While’s online operations are still on premise, it plans to move later this year, which may match up to Costolo’s prediction of a move in the spring.

Twitter, founded in 2006, has recently raised $200 million at a $3.7 billion valuation. The latest round was led by Kleiner Perkins Caufield & Byers.

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