#lemmy/#kbin has a problem that #mastodon hasn’t even attempted to solve; groups and what happens when they get popular.
#Communities, #groups, #magazines, whatever they are called are implemented as #Actors in #ActivityPub. They are basically just *very* popular users who boost a *lot*.
You can’t just distribute them across instances the way normal actors do. Whichever server hosts @technology@lemmy.ml or @technology@beehaw.org is going to get HOSED on the regular.
Information about post changes on the originating instance come in pretty much in real time, and get saved in the local database.
If the local instance is configured with pictrs support images are also cached locally.