The biggest surprise for me was the https://hexbear.net count, an instance I hardly interact with.
| beehaw.org | hexbear.net | lemdro.id | lemmy.blahaj.zone | lemmy.dbzer0.com | lemmy.ml | lemmy.one | lemmy.world | lemmynsfw.com | sh.itjust.works | sopuli.xyz | |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Community Count | 6 | 33 | 1 | 1 | 1 | 14 | 1 | 39 | 2 | 1 | 1 |
| Community Subscriber Count | 133450 | 663204 | 17052 | 15907 | 53006 | 356460 | 16257 | 851950 | 33586 | 16006 | 14093 |
The data this is based on comes from https://lemmyverse.net where you can just download a full json of the data they have (I excluded all communities marked as "suspicious")
EDIT: The data if you sort by active users last month:
| awful.systems | feddit.org | feddit.uk | hexbear.net | lemdro.id | lemm.ee | lemmy.blahaj.zone | lemmy.ca | lemmy.dbzer0.com | lemmy.ml | lemmy.world | lemmy.wtf | lemmy.zip | mander.xyz | sh.itjust.works | slrpnk.net | sopuli.xyz | ttrpg.network | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Community Count | 1 | 2 | 2 | 1 | 1 | 3 | 1 | 3 | 3 | 10 | 57 | 1 | 3 | 1 | 5 | 3 | 2 | 1 |
| Community Active Month Count | 2616 | 7363 | 5289 | 2952 | 2898 | 8898 | 11422 | 14910 | 13752 | 54949 | 338384 | 3602 | 12020 | 11469 | 37365 | 10897 | 10070 | 4107 |
Community Count:
Community Users:
They can be oriented to some type of content: For example, the many feddit.something are targetting people by countries or langages (.it, .uk, etc.). slrpnk.net is solarpunk oriented, mander.xyz science oriented. Litterature.cafe is books, reading and writing oriented.
And they can offer different moderation policies: People on lemmynsfw.com probably want to see NSFW content. lemmy.world has a policy against it. lemmy.dbzer0.com allow for open discussion about piracy that many instances forbid and so on.
It you don't see the difference in instances, it is probably that you are about fine on your local instance. But if one day, you hear about a community you can't access, maybe that is because it is blocked by lemmy.word and you could access it from another instance
If the dbzer0 instance allows piracy talk but I'm signed up to an instance that doesn't allow it, can I talk in their community or do I risk being banned from mine?
In other words, are my comments stored on their instance or on mine?
Lemmy stores your posts and replies on both your host server and on the server of the community.
One interesting behavior to note here that is different from reddit is that while comments on reddit belong to the profile of the person commenting and is then imported to view in the subreddit (this is why you can edit comments after being banned, and why there visible in your profile even if removed from a subreddit), on lemmy the target community is instead authoritative and your host server will by default respect a deletion by community mods on different servers by also removing that comment from your profile.
You can talk on their instance. If the moderator of your instance dis not wanted you to interact with this other instance they would have block it.
That I'm not sure. But I think there is a copy of the content you accessed on your instance. Maybe someone administrating an instance could answer you better than I did.
Your comments are stored on both. The "canonical" version would be on your home instance but every instance that is federated with your instance would get a copy of your comments. I think it's even possible to have your content removed from one instance but not another. One of my posts shows as removed in the mod log but isn't actually removed.
So which instance an account is from matters regarding which communities you can join? Huh.
Only insofar as some instances block communication from some other instances. Not mine though, that's actually one of the reasons I picked it. That and it being by an org that's older than the web and runs a public unix server and a bunch of retrocomputing type services as well as fediverse stuff. They started out as a dialup anime BBS.