I'm looking to offer a Q&A forum, and I don't want to recreate the wheel if a service already out there offers API plugins.
Products like ZenDesk have a whole system built around help centers and tickets.
Discourse and Disqus offer forum-like discussions.
WordPress has several forum plugins.
And that's just what I can think of off the top of my head. My assumption would be that a deeper search on Google will come up with a metric fuckton of options. This is a huge challenge, so I imagine there are tons of companies trying to fill that space.
Good luck!
