Bubble is essentially the core part of a site like reddit/kbin/lemmy/slashdot etc. in a lightweight protocol that is simple and immune to turning into ad-infested garbage due to the nature of gemini.

One big difference to kbin/lemmy though is that it isn't federated and probably won't be. Federation would greatly increase the complexity of the code and kind of go against the ethos of gemini. It IS possible, however, to run different instances of Bubble they just don't federate with each other. And depending how you feel about the privacy implications it would be possible to have a single "login" for any and all Bubble instances by using the same client certificate for each.

That plus the ability to subscribe to different subspaces via the gemini subscription spec you could also aggregate them by putting all your subspaces into an aggregator like comitium or a client etc.