Facebook’s Trending Feature Rolls Out, About Time
If you want to know more about a given headline, just click the subject and you’ll be taken to a new page where you can see all the content related to that story, including which of your friends has posted it or commented on it as well as any random posts related to the topic.

Trending topics on Facebook has been happening in a de facto manner for a long time, just because of the nature of social networking--someone spots a hot story, reposts it (often with a comment similar to “OMG, no way!!”), and all their friends repost it, repeat.
It’s high time that Facebook made this official. It’s one of those rare changes to Facebook that most people will probably be glad to see (right?), and it packages up the day’s topics in a neat little bow. Further, many people first see breaking news on Facebook, so it only makes sense that they’d be able to click for related content to those stories in a newsfeed rather than simply see it in a post from a friend.