feeds.reddit is yet another online RSS reader, but gladfully it has some innovative things that make it the best online RSS reader I know so far.
The idea is that it's a more social web feed (RSS) reader. First, it's got a great interface for reading feeds over the Internet -- it has key commands (see the faq) that let you easily breeze through stories while keeping track of what you've read and haven't read. Then there's a simple URL you can go to any time, anywhere (I visit it from my phone) to see stories you haven't read yet.
Second, just like on reddit, you can vote on items you like a lot. This will go towards creating a list of the most popular items but it will also train a recommendations system to try to find other items and other feeds that you'll probably like as well.
The only thing I don't like about it is a missing feature (I've already suggest it): a feature that would let you turn feeds.reddit into my Galxy concept. I mean, why can't I turn my http://feeds.reddit.com/my/ into http://feeds.reddit.com/myname and suddenly have a Planet setted up?