Also, RubyCorner does only cover blogs (not counting the video / photo sidebar) so you don't tend to get latest updates on libraries, and links to things outside of the Rubysphere. You also only get one link per hit, whereas on RubyFlow you can bind together a bunch of related interesting pieces in one go, or provide context.

Context is the final part. When posting you can write what you like and provide a little context to the links. This makes it a lot easier for you, as a reader, to know whether something is worth clicking. The problem with sites like Hacker News and Reddit is that you're going entirely on the headline. Sometimes you want more than a headline.. just a single sentence of context or a bunch of related links will do.

Hopefully that answers the question! Effectively RubyFlow's style is a cherry-picked, hand-written for context and quality alternative to browsing the social bookmarking sites, like Ruby Reddit : http://ruby.reddit.com/