One issue with the fediverse right now is that there are many redundant communities. Like !technology@beehaw.org, !technology@lemmy.ml, !technology@lemmy.world, etc all having essentially the same topic.
I think the easiest solution to this is to take reddit’s multireddit feature, allowing users to create their own “technology” multi-community that includes all the popular technology communities from all the instances. Thanks to federation, the user could interact with this multi as if it was one big community. Perhaps a way to share the multi with others so that all the component communities get federate-mirrored to the new user’s instance would be needed too.

I commented on this else where; perhaps this can be done via two folds:
1.
!technology@(note the distinct lack of instance domain), which is just a UI aggregation of all the!technologycommunities followed by the user, and:2.
#list$user@instance.domain(not fixated on the hash and dollar sign, just using different symbols than what we currently have to make picking out what kind of list we’re looking at easier) as a back-end driven, user managed multi where they could put!apple@instance.domain,!banana@instance.domain,!orange@instance.domaintogether into one aggregated list appearing on#fruits$user@instance.domain.The first type being front-end only shouldn’t require a lot of configuration or changes; the second type being back-end driven could offer a lot of flexibility (i.e.: privacy settings, if other users could see it/pull contents from it, etc.).