Trending is, for lack of a better word, the new trend in social media (did I really just write that? Someone take away my keyboard before I hurt myself and others). While it seems like ages ago at this point, Facebook added its own trending feature only a few months ago, and now Reddit is getting in on the action.
Technically, the entirety of Reddit is trending, that is how stories get to the front page. Subreddits, perhaps Reddit’s strongest feature, can now trend themselves on the front page of the site whenever they get an abnormally large amount of traffic. It seems like an attempt to lessen the fragmentation between Reddit communities and add a bit of unity to the service in general.
As TechCrunch points out, the Reddit community is fairly walled-off. Other than searching for a specific interest and joining that subreddit, there is very little in the way of helping you discover a new subreddit. Either it was something you searched for or something someone linked you to by chance (or something that got on the front page).
Trending subreddits will give them a chance to grow organically at a faster pace.
Currently, /r/oddlysatisfying ,/r/Showethoughts, /r/JapaneseGameShows, /r/H1Z1 and /r/minimalism are trending on Reddit’s front page.
Reddit also assures us that it has anti-cheating algorithms in place (Reddit is famous for their anti-cheating guards) and that it will not allow NSFW subreddits to trend. Subreddit administrators can also opt out of the program, if they would prefer to keep their subreddit small.