Avoid Discourse.org's Forum-like product Discourse.
UPDATE: 20161202 - I can now recommend people instead consider using NodeBB, NOT Discourse. http://nodebb.org Much better community & developer environment, much better documentation, and far less of a kludge product than Discourse.
I was evaluating Discourse.org's forum-like product Discourse for a major project for which I was asked to be the technology consultant, currently under NDA. We thought it would provide many features necessary for a portion of the project. And while Discourse may some day realize the hype of its possibilities, I have to strongly recommend that people do NOT consider using this product in a production setting at this time. If they are still around in 3 to 5 years, I may have cause to reevaluate, but for now, it is recommended to go with other much more robust, well-developed, well-supported forum related products. The end result is a huge waste of time unfortunately. You can read more about the problems with the product, founder, support, and community, here: http://techtalkhawke.com/news/discord-with-discourse