Seeing random tweets in your timeline, like tweets favorited by people you follow? Twitter CEO Dick Costolo has offered up one reason why: “you get favorites when you pull-to-refresh 2x and we have no new tweets from follows both times.” Costolo’s tweet follows Twitter’s recent plans to begin showing tweets favorited by people you follow and popular tweets from people you don’t follow in user timelines. Until now, however, it wasn’t clear exactly when or why Twitter would bring in these kinds of tweets. The company’s decision has angered some users, but Costolo’s tweet may indicate that Twitter’s new strategy might be more of a last resort (when you don’t have any new tweets to load) than a core feature. But this doesn’t change the fact that people use faves for lots of different reasons — and not all of these reasons mean that a stranger would find the favorited tweet very interesting.