I would definitely consider that a serious potential issue, if for no other reason than so many communities will likely find a use for tags based on the nature of the community structure.

For example, I could see a ton of communities having tags for things like modposts, new member intros, meta topics, memes, questions, reviews, how-to’s/tutorials, guides, etc. and that’s just for broad post types that would apply to thousands of communities.

I think letting users manually make their own multi-lems, perhaps with the ability for communities to sort of team up to make uber-lems of closely related communities to help users discover more of them…but sub, unsub, multi, and un-multi as they see fit…is likely the best approach.

Maybe don’t take disagreement so personally?

I too would like to do this myself and not have AI or anyone else decide for me what content gets lumped together.

I predict that this is also an issue that will slowly resolve itself over time, as critical masses of users gradually coalesce around one community, or more…but only if the extras are distinct in some way…which would very specifically be made more difficult by the sort of programming you’re proposing.

I’m not saying there’s no merit in your suggestion, only that it may not be the one-size-fits-all solution that you seem to think it is