My friend Ben and I built this webapp, pleasexpla.in, during our first organized hack day in Seattle. With pleasexpla.in, a user creates a discussion and can share it with others via its URL on twitter/facebook/reader, etc. You can also subscribe to a conversation in RSS. Ideally, I see this as enabling conversations in places where they can be difficult at present– inside of an RSS reader or on twitter for anything that doesn’t fit in 140 characters.
We’re hacking on it a bit in our nonexistent spare time, so we’ll see where it goes.