In-short:
a. As long as they support the #webstandard#ActivityPub
b. Regardless which software your server/community you joined is using.
c. Or, which server/service you are using (or you run your own)
You can follow, reply, share, with any user, anywhere.
This means that: 1. There are countless of users in the #Fediverse "network" 2. Potential wider audience 3. You can run your own single-user, or by invitation, server 4. Follow users on IG-like/YT-like/… platforms without creating a new account. 5. Encourage interoperability
You don't stop using a refrigerator because the brand you bought broke down immediately. You find a new brand and use it too.
It's the same with #Linux, you find a new distro; and the #Fediverse, you find a new platform and server.
Another thing people are forgetting: when you first joined Twitter, Facebook, or Instagram, you never had followers. You built it by (1) learning the platform; (2) using it; (3) interacting; and (4) building connections.
Same process in the #Fediverse network. It's not magic. 😉
Yet another. It's a misconception that the #Fediverse network (or #Mastodon software in particular) is for, or dominated by, techies. There are a lot of Fediverse servers with preferred themes.
Some I've seen: #anime, #kpop, #LGBTQ, and religious servers. They are thriving. 🙂