Twitter on Wednesday acquired the artificial intelligence startup Whetlab, bolstering the analytics capacity that is becoming increasingly important for social networks. Terms were not announced for the deal, which was disclosed in a tweet by the Twitter engineering team and on the website of the Massachusetts-based Whetlab. Artificial intelligence can be used to determine the most relevant tweets and advertising messages for each user or to better filter spam. The move comes with Twitter searching for a new chief executive following Dick Costolo's announcement that he is stepping down.