Hey new people and those thinking of joining, you do NOT need to sign up on huge servers!
You can follow and interact with people on any server from any server, the servers are connected.
It would really, really help the network right now if you could sign up on medium or small size servers. You will still be able to follow and interact with whoever you want, and the network as a whole will work much better.
A good safe place for beginners to find servers to join is https://joinmastodon.org/servers
You also don't need to be on the same server as your friends.
You can find each other from different servers by exchanging account addresses, here's how it works:
https://fedi.tips/how-to-use-mastodon-and-the-fediverse-basic-tips/#WhatsMyAccountsAddress
It's a bit like exchanging phone numbers!