compare and contrast to reddit: text but extremely simple, intuitive, you can follow conversations, know who is talking to whom, respond, link, etc.
I'm fairly technically proficient and I have a hard time figuring out how to "onboard" myself to Reddit and to understand the whole system. It's relatively intimidating.
If we want to stick to text-only, I think HN is actually a better example. Of course, Facebook is really the pinnacle of broad accessibility.
I've said all this but either is INIFNITELY better than twitter, especially twitter's standard web client. TweetDeck makes the thing barely useable.