Im joining in on the reddit ditching thing, and was kinda worried at first that i wouldnt be able to like use it the way i did reddit as it feels like a whole new place, but after engaging with posts and people and actually being a part of lemmy rather than being lurk mode all the time i was pleasantly surprised with how easy it is to become a member of the community, theres a reasonable amount of subs (or whatever the other word for em is) that fit my interests, enough linux content and shitposting for my liking, and the overall random posts made by people equally fed up with Leddit. (also i admit i used reddit a little cus there was this post on the fedora sub showing how to fix a sound issue i been having after a recent update)
No, it indexes posts from other instances only when you are looking for them. Also, i’m not sure, but as far as i remember, it indexes only last 20 posts + every post referenced in already indexed posts on the first lookup(then - everything). I’m not sure about it, don’t quote me.
A server will only pull in everything from a community once at least 1 person on that server subscribes. Then it will start pulling in every new post and comment as soon as they’re up.
Oh, so it’ll pull everything. OK, then looks like i’ve made it the fuck up.