You can only sub to them from your home instance. So you have to go to the communities section of your instance then search for a community, click on it from there, go to the sidebar and subscribe.

To sub to them on the web UI, you have to search for them on whatever instance you're logged into (using !community@instance syntax), click into the community, and then hit subscribe from there. It took me a bit and some googling to figure out. Also there may be some instances that aren't connected to each other or something. I don't quite understand that part yet.

This is the problem, you came too early. You'll have to engage a bit more in conversation and carrying over things from Reddit. Think of it as an investment.

The beauty of Fediverse is that all these Lemmy and Kbin sites can talk to each other and you can participate in any of these Lemmy or Kbin instances by only signing into one, while with a centralized monolith platform like Reddit you are at the mercy of a single corporation which means they can pull the bullshit they are pulling right now. They feel empowered to do that because all of the useful information is in a single website. Fediverse solves that but it does add a little bit of complexity.

This instance is already becoming very big so feel free to participate only here, but you're welcome to try other interesting communities in other instances without having to abandon yours. Go to the Communities tab and then click the All filter.

Lemmy as a whole is already reaching or upwards of 10000 people, that is a sizable critical mass to begin posting stuff. The power is in the hands of users here.

The semi-decentralised nature is part of the point of the service, you can join a small, local server and still subscribe to communities on larger instances and it (in theory) all syncs up and works.

multiple servers spreads the load, heck, you can host your own lemmy instance on your own hardware and still seamlessly communicate with large ones like lemmy.world once it synchronises.

Downside (apart from the inevitable shutdown of smaller servers without admins willing to put the time and money in leading to lost accounts) is that communities aren't automatically fetched, so sometimes you need to paste the url into your instances search bar to get it to sync to your sever, then you can subscribe. I picked a medium size server on the other side of the world because I had no friggin idea what I was doing but now my feed is full of content from all of the big servers.

I think the slow and steady development from the last few years will now speed up a lot as more and more people use the service and find new limitations, new features, fixes and optimisations will come.

So far, it's handled the massive influx of users very well.