Looking through BlackBerry World there are plenty of third party apps for Reddit users. If you're a big Reddit user, one app you should check out is Alien Flow for BlackBerry 10. Built using cascades, it packs a bunch of features Reddit fans will love. From multiple account support to voting posts up or down.
If you haven't heard of Reddit before, it's a website where users can submit content in the form of links or text, then other users give those submissions an upvote or a downvote depending on whether they think it's newsworthy enough. This determine's whether or not the link stays on the frontpage. The frontpage is composed of the top stories from the subreddits you subscribe to. It's the place to find the top news of the day. You can customize your own personal frontpage too. Subreddits are basically mini-communities where submitted links follow a particular theme, for example, BlackBerry.
Alien Flow Features:
There are a couple of other features available though these require an in-app purchase. These features include: entering an arbitrary subreddit to view and adding subreddits to your favorites.
The developer has many more features planned, including the ability to submit posts. The app is free with in-app purchases to get more features, though the free version does a good job on its own. Certainly an app to try out if you're a Reddit fan.