There was a non-forum software that I currently can't remember that was context/content aware, and would use pre-configured tags and relation between tags to generate a tags automatically. It was pretty accurate, and worked very well but I can't remember it at all anymore.
Pretty sure it was a CMS however.
I love using tags over other things but every community software I've seen either does it horribly as a after-thought, or the software itself doesn't fit well for what I need (lack of functionality). Like I like Discourse/Flarum to some extent, but they're too barebones and not really functional for my needs at all.
Please note that I do not have the time to give personal support for installations. This addon is working perfectly on my forum AVForums, so I will be updating it with maintenance releases and new features as and when they are needed, which...
I'm very surprised we don't have a function/add-on that, via cron, automatically applies tags to content where the content, via 'weight', matches existing tags. Would save admin/curator time and effort, and greatly increase user experience (and SEO?).