Bluefin Labs, a social TV analytics company, got acquired by Twitter. While details of the deal have not been disclosed, Business Insider has been told it is Twitter’s biggest purchase ever (previously TweetDeck’s acquisition of $40 million was thought to be largest). Bluefin has raised $20.5 million and is backed by a multitude of investors including SoftBank Capital, Redpoint Ventures, Lerer Ventures, among others. [Source: Business Insider]