Beehaw is a Lemmy instance. However, they defederated from two huge instances, because they're open registration, and the four BH admins felt overwhelmed with the incoming traffic and unable to manually block trolls, so they decided to just separate from a large chunk of content rather than get it under control.

I'm on one of the two defederated instances, sh.itjust.works, and I can neither see what's posted there, nor can a BH user see what I post (or what's up on our server, for that matter.

The other big instance is lemmy.world.

BH has very specific rules for what's okay over there and what's not. Check them out and see if you're willing to live with the defederation for the sake of what their admins define as safety.

Lemmy and beehaw are not separate. Beehaw is Lemmy. It's a Lemmy server/instance. Beehaw just chooses not to participate with a bunch of other instances.

The main difference between instances is how they're run. Like you're asking about just now, beehaw is run very conservatively where they tend to block more quickly and try to make their instance as safe a space as possible, while others may be more laissez faire or something in between. Some may have a topic focus. But which communities and how many are on an instance basically doesn't matter.

Lemmy is the software a lot of the Reddit style fediverse websites run on. Many of them include Lemmy in the name such as Lemmy.ml and Lemmy.world, but others don't include Lemmy in the name. Beehaw.org is another website that runs the Lemmy software, it just didn't put Lemmy in its name. Beehaw does have an uncommon configuration since the down vote ability is disabled there, but it still is Lemmy at its core. Beehaw did defederate from some of the other big Lemmy servers because they were overwhelmed with trying to moderate that much content and those servers reportedly had open sign ups which led to a big influx of spammy bots, so Lemmy.world and beehaw.org are invisible to each other right now, but the admins of Beehaw have expressed a desire for more granular moderation tools in order not to have to defederate from such large servers as a whole in the future.

Kbin is a different software altogether so the kbin servers such as kbin.social and fedia.io have a different layout, terminology, and some different features than the Lemmy based servers, but Lemmy and Kbin both use the ActivityPub protocol to send and fetch data, so you can post between the two platforms as if they were on the same server. I am browsing this post and writing this reply from kbin.social.

They are all the same, but the only difference being the rules. lemmy.ml was one of the earliest instances, run by the developers themselves. beehaw.org is a community that promotes positivity, they've defederates from sh.itjust.works and lemmy.world. lemmy.world is the largest instance. Some instances are hosted in different countries, which means different laws apply. Some instances are piracy friendly (lemmy.fmhy.ml and lemmy.dbzer0.com).

Then there are instances that are basically isolated. They've been defederated by many instances.

lemmygrad.ml - promotes Authoritarian Left politics

exploding-heads.com - many alt-right content gets posted there

Beehaw.org places a high priority on censoring content that would offend folks like the LGBT crowd; they've been more-willing than most other lemmy instances to defederate from kbin or Lemmy instances that they consider sources of problem users. For some folks, that's great, and for others, that's not what they want.

It is currently a little hard to find the community rules for instances that give you at least a basic idea of what an instance is "about". And not all instances are aiming for something, but for those that are, it's nice to know about it. Sign up for pawb.social, and you're on a furry-oriented instance, for example. For Lemmy instances, trying to join normally shows a page that talks a bit about the instance rules. For kbin instances, you can see a short writeup from the instance admins at /terms, like:

https://kbin.social/terms

You can get there by clicking "Terms of Service" at the bottom of any page.

Pretty much choose the instance that has rules you agree with, the number of communities on an instance shouldn't be a factor because you can browse (and participate in) communities on other instances. Edit: Also, using some smaller instance might make the experience better for you, they're not as overloaded and thus faster.

Beehaw is a Lemmy instance/server.

The instances/servers talk to each other to spread out the load so it's decentralized.

From a technical standpoint, there's little difference between instances. They're all running the same software at their core, and connected to the same network of websites.

Some instances, such as Beehaw, seem to strive more for building an actual community around their instances, while other instances aren't as interested in that and are focused more on just being another available alternative entry point to the Fediverse. I've not looked around Beehaw too much, but from what I understand, they seem to want to create a highly-positive environment for their users (hence why they've had to temporarily defederate from some instances, until there are better moderation tools available for them to keep trouble-making outsiders away from their community).

Some instances may focus more around a particular political leaning, some may be specific to a hobby like video games, etc. But at the end of the day, there's nothing stopping you from registering to as many or as few instances as you want. For the most part, they're all connected to the same overall network, so you'll typically be seeing the same content no matter which instance you browse from.

Keep in mind that your username is going to be based on the instance you sign up with. For example, I'm Chozo@kbin.social, and while Kbin and most instances will just show that as "Chozo", my account is still permanently tied to kbin.social, even if I'm posting on threads from lemmy.world like this one.

I think your best bet is just going to pick whichever feels best for you in the moment. I think for most users, it doesn't really matter. If you're looking for a specific community, then check 'em all out and see which one fits your needs best. If you don't care and you just want something that works, then any of the larger instances are probably going to be sufficient for you.

You might want to check out https://github.com/amirzaidi/lemmy. I stumbled upon it. Beehaw defederated Lemmy.world (info.) This section on defederating may help you understand that if it's unclear.

Most of us are also new to the Fediverse, but learning every day. Welcome!

That's like asking if there's a major difference between email and gmail

All of the federated sites push and pull content using ActivityPub (the technology that connects them all together), but they all seem to differ in the way their website presents the data and how you interact with things.

For example there's an upvote / downvote button on kbin.social for articles, but also a boost button. I've heard that some places only use the upvote and others the boost (or whatever they call it)

I found it easiest to just pick a place that looks decent and is chill and go from there 🦙🦙