At first glance it may seem somewhat strange for news organizations to favorite Tweets from their main account. After all, can you really be non-biased AND have "favorites?" But the "Activity Feed" is Twitter's new beating heart, and if you watch it for long enough you'll notice that different organizations dole out favorites in surprising ways.
Disclosure: @BuzzFeed favs a bunch of stuff with few discernible patterns (stuff from staffers, reactions to posts, etc).