They’re a lot more resistant to it than the centralized softwares.

Stuff you post here has some small chance of remaining un-stored-forever. Obviously people can read it and store it, but it’s not systematically indexed and processed like Facebook Reddit etc. Bots go around indexing the big instances, and it’s fairly likely that they’ll hold onto the data. Aside from that it doesn’t get “centralized” anywhere. It might not be a bad idea to delete your comments after a week or two if you care about long term privacy, not that that’s bulletproof, but not a bad idea.

Voting, weirdly enough, is basically public. If you’re upvoting or downvoting things, more or less anyone on the network who’s tech savvy can dig out the information of who voted on what. Subscriptions are also basically public.

“Reading” actions you take on Lemmy sites – searches or viewing things – is probably completely private. The only people who can see it are the individual instance operators, and it’s legitimately unlikely that they’ll ever look at it, much less hold onto the data once the logs get rotated or do anything with it aside from delete it.

So the TL;DR is it’s way better here (mostly because the servers are privately operated by people who at worst, don’t give a shit what you’re doing, and at best would actively want to defend your privacy most likely).