A lot of good points have been raised already, but I thought, I’ll still add my 2 cents here.
Having analyzed the current forum software landscape as part of a migration project for a medium-sized community focused on gaming topics, I feel it doesn’t look too bad for Discourse - both because of reduced competition (e.g. XenForo seems to be struggling with development right now) and because it has a number of useful qualities. At the same time, there are a number of factors that make adoption of Discourse as a community platform harder than it needs to be IMO.
Maybe to start with the positive things:
(Major)
- Open source project with continuous development and a healthy community (both the amount of support provided here on meta and the willingness to accept pull requests are good signs IMO)
- Available both for self-hosting and as a hosted service - both with equal feature sets (at least as far as I can tell)
- Suitable for use with mobile and desktop clients
- All the typical features people are used to from social media (likes/reactions, tagging users, reply notifications, easy embedding of media)
- Live updates and notifications are part of the core
- Import scripts for many common other forums
(Minor)
- “Tracking” as a state between “normal” and “watching” (it’s probably my favourite smaller feature of Discourse)
- Posts can be written in markdown (might just be me, but I really enjoy being able to format posts without all those BBCode brackets)
- Persistent drafts for new posts
- Container-based deployment is possible
- SEO-friendly URLs for posts
- Data explorer! (again, probably mostly me, but it’s really a lot simpler to use the Data Explorer with its reference to columns in the common tables than to dig through a database directly)
With that being said, there is a number of points for improvement:
(Major)
- The UI/UX, especially of the main page - this has been mentioned already, but I there is almost a “baroque abundance” to the UI of Discourse, with so many things being accessible through at least two navigation paths (the side menu is probably the worst offender; it is not the only one, though), while at the same time other options are missing (e.g. I don’t think I have found an option to look at the list of topics I am tracking or watching when there are no new replies; but maybe I just haven’t found it) and the metaphors for different screen areas are not really clear/some functions are not available at the places where I would intuitively expect them. I will try to spin up a dedicated post for this in the coming weeks, since I feel this warrants a discussion of specific details.
- A similar thing could be said about features - and personally I agree with @piffy that the use case for public chat on a forum that also has private messages with live notifications isn’t really clear. However, I’m willing to accept that maybe I am simply not the target audience for this.
- Discourse doesn’t make it exactly easy to structure content, especially when coming from a classical forum with a multi-level category hierarchy (for the community we are planning to migrate, we regularly have three levels of nesting). Most of the software seems to suggest that content should ideally be structured into a small number of categories and that the rest should be handled with tags (and I think for communities in which this works, there’s really no issue). Now sub-categories do exist, but since they neither show up in the side menu nor in the category list, it feels like they are more tolerated than embraced throughout the software. At the same time, category groups are not of the core, and a clean, visually appealing look like that of the Blizzard Diablo forums seems to require heavy customization. This is the point where I saw people bounce off Discourse hardest.
- The lack of polished, clean first-party themes is making it much harder to get started quickly. Personally, I find the category page to be the most problematic since it will, by default, look like someone accidentally dropped a color palette on it, and I don’t have a good idea yet on how to work around this (because different category colors are still quite useful in the latest list)
(Minor)
- For a software that handles pretty large communities, the moderation tools in Discourse are surprisingly bare-bones. I would have expected the ability to easily start a discussion on reports within the moderation team in more complex cases. Similarly, I would have expected a warning point/warning level system by default. This technically could even be classified as major, but I don’t want to rule out that I simply haven’t found the right options yet.
- The lack of branding that extends to not even having a footer means that it took me a bit until I started realizing that Discourse was already used in a number of larger communities. Now I don’t think the lack of obvious branding is a bad thing per se, but potentially the use of Discourse could be indicated in a comment of the rendered HTML, so it would be available to anyone looking at the source code in the browser. That way brand awareness could be increased a bit.
- I tend to say that Discourse is overdoing it a bit in terms of gamification/mechanics of user activation. Getting “achievements” for even the most basic functions feels quite weird to me. Similarly, as expressed in the respective thread, I’m not the biggest fan of messages like “we haven’t seen X in a while”, “Y is new here”. I know new user tips can be deactivated, but I think it’s more a question of having a way to just tone it down a bit instead of completely removing them (an option to turn off the user messages on a preference basis would still be great, though).
Edit:
Forgot about moderation tools in the first iteration and added a bullet point for them later on.