Seeing random tweets in your timeline, like tweets favorited by people you follow? Twitter CEO Dick Costolo has offered up one reason why:
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.
Twitter's methodology for choosing when to show favorites will most impact users who don't follow many accounts — the users Twitter is trying hardest to impress. The company seems to be hoping that, by splicing in content from around the Twittersphere when there isn't anything else to show, users will be motivated to follow new accounts they might not have otherwise found. Twitter currently has a Discover tab which shows these same kinds of tweets, but it's not clear how many people frequently use that feature.