Even Twitter uses this -- they are a free, open source forum (the #1 on the internet). Everything on the forum is very intuitive (similar to this ticket system -- you can even paste images directly from clipboard, etc).
> Here is a sample <
They have a HUGE, JSON-based API with the ability to do anything and everything. They also offer plugins. If you made a plugin, and because they are open-source, you could have official GameSparks integration! Imagine being able to even login to a forum and have access to all your data.
DigitalOcean also offers a 1-click setup for the forum, so it's relatively easy to setup for end-users, too. Everything is setup via the website after the initial setup.