TWITTER has raised US$200 million in financing in a deal that values the company at US$3.7 billion, a spokesman for the microblogging site said on Wednesday.

The investment came from Silicon Valley venture capital firm Kleiner Perkins Caufield Byers and existing investors, Twitter said.

The company added two new board members -- FlipBoard Chief Executive Mike McCue and DoubleClick CEO David Rosenblatt.

The moves come two months after the four-year-old company handed the job of chief executive to Dick Costolo, the architect of its new advertising efforts, a sign that making money is a priority for the service.

Twitter, which allows users to send 140-character text messages, or Tweets, to followers, is one of the Web's most popular social networks, along with Facebook. Investors are watching the service closely, hoping one day to buy public shares of the company.