Others have told you how to access communities on other sites, so let’s focus on why it is this way.

Websites that use ActivityPub – that is, websites running things like Lemmy, Mastodon, PixelFed, PeerTube, BookWyrm, FunkWhale, and even some WordPress sites – are engaging in an auto-syndication or auto-mirroring system. If I have an account on lemmy.world (LW), I can post something to a community on lemm.ee (LE). That post will be sent by LW to LE, and then LE will send it out to every other website that is subscribed to that community. That means that you, here on lemmy.ca (LC) will be able to see it once LC receives it.

What you will be looking at, though, is a copy of the post on LE. And, indeed, what LE is hosting will actually be a copy of the post that originally got posted to LW. Everything’s happening locally here. We’re all interacting with local copies of material that is being syndicated to hundreds or thousands of other websites.

When you comment on my post, that comment first lives on lemmy.ca. LC will forward it along to lemm.ee, and then LE will distribute it to all of the other sites. That way, my account on lemmy.world can see that you said something.

This is all really neat, but sometimes it can seem too clever by half. For instance, these websites do not syndicate with every other Fediverse website in existence. It can’t. There’s no central directory of websites, there’s no phoning home, so one website cannot know about the existence of another unless someone goes out of their way to introduce them. If I were to start a new Lemmy-based website today – kichae.social – I would not be able to find any communities hosted on LC, LW, LE, or any others using the search feature. My website wouldn’t know they existed, and would not have a list of communities they host. Similarly, none of those website would know about mine, or any communities I’m hosting.

The network grows by direct, personal intervention by users. If I want to see !lemmy_ca_support@lemmy.ca on kichae.social, I need to copy the community’s URL and then paste that into kichae.social’s search bar. This will tell Lemmy to go and fetch whatever it finds at that address, assuming it’s a community or post. Once it’s done that, though, I can subscribe, and content will start to flow from LC to kichae.social.

Well, at least, content from this community. Syndication on Lemmy happens on a community-by-community basis.

Fediverse subscriptions also, generally, work the same way magazine subscriptions do. You don’t get the back catalogue once you’ve subscribed. It’s point-in-time-forward only. Some sites do pull in a sample of posts – I believe Lemmy-based sites work this way – but not all will.

On larger or more established sites like lemmy.ca, this isn’t really an issue. But if you find yourself wanting to run your own site, or think you’d prefer the experience on a smaller, niche fediverse site, it’s good to keep in mind. You should be able to access stuff from other websites, but you might have to put in more legwork in a more rarefied space.

Think of it like email. You can’t log in with your gmail account on hotmail and vice versa, but you CAN send email back and forth. Ditto Lemmy. You can subscribe to communities on other servers, upvote, etc.

Hey there!

You don’t need to log in to lemmy.world to view or interact with the content there. You can follow/subscribe to communities there by searching for communities and they’ll appear in your home/subscribed feed. You can also make posts to those communities.

But, you can only create communities (‘subreddits’) on your home instance.

Edit: even without subscribing, communities from other instances will appear in the “all” feed. You can also vote and comment without subscribing.

And just to answer your question about accounts, your account is specific to your instance. You can’t log into lemmy.world because you don’t have an account there. So, accounts aren’t shared between instances but content is shared (as I described above).

I wouldn’t go to lemmy.world directly. Rather, click on Communities -> All and just start subscribing to a bunch of stuff. Many of them may be hosted over at lemmy.world but it doesn’t really matter. Once you subscribe, it all comes over to lemmy.ca and you can post/comment/whatever.

If you use one of the mobile apps such as Voyager or Raccoon you’ll be able to browse and see all of the federated communities on the All tab.

If there’s a specific community that you want to find and follow you also have the option to search for it👍

Let me suggest a good default feed setup that I like.

• Subscribe to any community you might be interested in, from lemmy.ca and other instances. If there are duplicates e.g. Android@lemmy.ml, Android@lemmy.world, subscribe to all duplicates.
• Set the feed filter to Subscribed and the sorting to Scaled.
• When you get bored or want to check what’s up with Lemmy general, switch to All + TopDay/Hot
• Play around with the sorting and filtering. You can save the default setting you prefer in your profile.

Don’t forget to contribute by voting, commenting and posting. Don’t just lurk.

In my opinion, the best thing to switch between Instances is to use an app:

https://lemmy.world/post/465785