Is lemmy.world more active than lemmy.ml?

https://lemmy.world/post/141380

Is lemmy.world more active than lemmy.ml? - Lemmy.world

So apologies if this is a stupid question as I’m new to Lemmy. Came from Reddit. I moved to lemmy.world and have noticed that lemmy.ml [http://lemmy.ml] has been popping up as another featured instance. What differs from lemmy.world vs lemmy.ml [http://lemmy.ml]? Is .ml more active? Part of why I ask this is because I downloaded the lemmur client on my phone and it defaults to lemmy.ml [http://lemmy.ml]. (Yes I’m aware that app is no longer being maintained) Again apologies for the stupid question.

They're federated so we can interact from both networks I think. It's more populated here so it's more active.
Yeah I know we can interact with .ml (which is simultaneously weird and cool) but that answers my question for sure. This place is so cool.
What’s even crazier is that you can also post to Kbin which is a server running completely different software
See that's the part that trips me out. I understand the concept pretty well now. What I don't understand is how in the fuck you can interact with Kbin and Mastodon, even though they're built on instances.....I just don't get that. It's amazing.
Kbin, Mastodon, Peertube, anything in the Fediverse adheres to ActivityPub standard, which is the protocol that all of these sites use to communicate.
On a side note, what exactly is Peertube? I've been hearing things about it but I have no idea what it is. Is it like a YouTube alternative? Or is it like P2P YouTube?
I am going to be honest, i don't really know either, I just included it in my example because I know it's federated