Okay, it’s actually 18955 at the time of this post. I’m looking at https://lemmy.fediverse.observer/list and lemmy.world has already passed beehaw.org by a large margin for second place.
Can’t wait for this place to start filling out!
That’s pretty much it for me. There’s a lot of complexity in hosting that you don’t have to do if you use someone else’s instance. There’s a risk that their server goes down, but most people who start big servers know what they’re doing.
Its also advantageous to join the instance you want to interact most in. Interacting across instances is possible but still a little buggy. It’s harder to find communities, and once you do, sometimes posts don’t load.