Commentators see the move as an attempt by Twitter to shore up its growing advertising business, which is expected to push the social network to $1bn in revenue this year.

Bluefin tracks online conversations about TV shows, brands and commercials. It has signed some significant deals in the four years it has been running, including working with Starcom MediaVest Group to analyse social chatter around TV shows and find placements where brand receptivity and engagement is highest; and with ABC to track reaction to major events during last year’s presidential campaign.

It was also part of NBC’s billion-dollar Olympics research lab, providing data on social media conversations surrounding the broadcasts, the athletes, the sport, and the commercials.

Business Insider was the first to report Twitter’s acquisition of Bluefin. The deal is interesting in light of an agreement Twitter signed with Nielsen in December to start producing ratings based on the social reach of TV conversations. It’s not yet clear whether the Bluefin acquisition supports this work or will run separate from it.