I have a real disdain for tags for user generated content. Every site I have seen use tags I end up having to wade through a ton of spam or vaugly related content to whatever tag I am looking for. The only exception I can think of is Hashtags for twitter but that is due to the character limit.
I understand that people see tages as a solution to crossposting but I think people overlook the benefits of crossposting. Being able to have seperate conversations on AI art in an art community vs programming community is more useful to me than having a single post that both communities comment on.
I'm not saying it couldn't work but I don't think it would be as trivial as that.
I also like that subreddits were able to foster their own communities with different expectations and cultures. I feel like using tags you are more or less forced to have a single overall community vs many smaller ones.
The first is an account setting for the user that allows them to hide all comments from people that arent part of any community that the post shows up in: https://github.com/kraftman/TenTags.io/blob/bc6f3046dda4815b...
The second is to allow filtering all of the comments by the communities the comments came from: https://github.com/kraftman/TenTags.io/blob/dev/api-cdn/view...