I originally chose to make my account on lemmy.world since all the content seemed to come from there. But I’ve since learned that I can fill my feed with stuff from any instance so it feels like it doesn’t actually matter if I’m on lemmy.world or not. At the same time, Lemmy.world seems to be frequently under attack so I’m wondering if I should change instance but have no idea what I should even be looking for when choosing.
Yes, there are multiple people that could have your username, and you can have multiple accounts with the same username. For example, this is my third TheSaneWriter account on this platform, my first was on the defunct instance VLemmy and my second is partially active on the instance lemm.ee. Same with /c/politics, there can be as many versions of that community as there are instances, though the largest will probably be on lemmy.ml and lemmy.world. Most Lemmy frontends have 3 feeds, Subscribed, Local, and All. Subscribed is only communities that you are subscribed to, you can subscribe to any community on any instance from any other instance as long as your instance hasn’t defederated from them. Local is all of the communities on your instance, All is all of the communities that anyone on your instance has subscribed to. You can also block communities from any instance that you would like. Here’s a fairly active Ukraine community, !ukraine@sopuli.xyz. There are other ones out there, but this one is the most active. I found it here: https://lemmyverse.net/communities?query=ukraine. Lemmyverse can see any community on any instance that is public to the internet, so if you are ever looking for a community feel free to check there.
This is the best explanation of the difference between Subscribed, Local and All that I’ve run into so far. I thought I understood the All tab but apparently that was a huge misconception I had before asking this question.