Following the inclusion of hashtags, Facebook began testing a Trending box during the late summer last year, showing popular topics in the upper corner of one's account much in the same way the aforementioned microblogging site does. Fast-forward a handful of months, and Facebook has now begun rolling the new feature out in certain (yet unspecified) countries, while mobile users will have to keep waiting as testing is still underway.
The idea behind Trending is simple, and could be handy for those who want to see the bigger social picture rather than live in the bubble of their friend's list. Trending items, which are topics popular in the moment, whether recent events, news, or something else entirely, are listed in a small box in the top-right corner of one's main page -- not quite in the News Feed, but close enough.
Not all will be seeing the same trending topics, however, with the list -- which is slight in nature with only a handful of topics -- being personalized for each user. Some topics displayed with on Facebook-as-a-whole trends, but others will be trends within topics you're interested in, as determined by your past Facebook activity, likes, and other applicable settings.
With each trending topic comes a small blurb that explains what the topic is about, and clicking it will then pull up posts related to the topic, making the social network altogether Twitter-esque. If you're not seeing the box yet, hang tight -- Facebook hasn't said which regions are getting it, and when it will roll out to others, nor when it'll be showing up on mobile.
SOURCE: Facebook Newsroom