Discourse

Not ready for production. This product is high on promise, but needs another 3 to 5 years to mature (if it survives that long).
A great range of promised features, but not ready for prime time. Consider other products.
Discourse is not production worthy. It is extremely fragile, with a long list of inter-dependencies on other products, with any updates to any in the long chain easily breaking Discourse.
Despite being recommended to install inside of Docker, Discourse's very fragile dependencies also mean it does not do well outside of a very narrow set of platform configuration options (alternative Linux distros problematic).
Riddled with a vast array security issues, that do not appear to be taken into consideration.
Support is very poor, with a long list of backlogged issues still unresolved. The community is very active, and attempts to help but is very scattered in the support provided. Oversight of support and development is by a single developer that has a reputation for being very immature, very insecure, and often deletes any criticisms and many of the bug reports.
If the product matures, check in again in 3 to 5 years to see if improved, otherwise do not consider using this product in any production environment.

[Edited by rightsfight, November 20]

I love Discourse because it's robust and very powerful. It has a ton of features, is open-source and easy to setup (needs a bit of technical knowledge, but they have a ton of guides to help over that). I totally recommend Discourse to anyone looking for community creation/management tools!

Discourse is pretty awesome forum software - best I've tried!

If it could to voting and edit suggestion like Quora it would be completely killer!

Plans start at $100 / month

You can find a full listing of most of the current sites using Discourse here for examples

https://meta.discourse.org/t/please-visit-our-discourse-forum-directory/3102

Highest used discourse forums found here:

https://meta.discourse.org/t/biggest-busiest-discourse-forums/30674

Discourse is also founded by Jeff Atwood, cocreator of stackoverflow.com

I personally use discourse forums a lot as a user and find it intuitive

PROS

• Automatically uploads images when you post it on a forum
• Customizable
• Friendly badge when you post things
• Clean UI
• Higher tiers of paid service lets you bulk download all your forum posts

Great software, open-source, and very customisable!