There are also tags, which may be followed as well that are usually topical. That helps 'outside my feed' discovery. Also, you can select a certain amount of external posts to filter into your feed for some serendipity. Finally, you can ignore specific users and tags to control for what type of external posts filter in.
We aren't huge, but we've got a pretty eclectic range of content.
Using this model, bloggers and content creators can post their own links. If people aren't interested, they simply won't see them. -There are no community pages to be polluted. IMHO shared feeds are key to the decline of these types of communities.