Comment by unshavedyak

Disclaimer: Novice, who also signed up. I've barely looked into anything, this info is just my experience.

So it's mostly like email. Logic that would work for email i think works for Mastodon. Just like with email you can generally email anyone and anyone emails you, the same applies to mastodon in my experience. However, if a server is being too <insert reason here> for your server's admins, they may block the entire thing. I don't know the finer details of how blocking can take place, but my loose belief is that you won't see posts from blocked servers. Though i may still be possible to explicitly follow someone on a blocked server.. i'm unclear there.

This amount of moderation will obviously vary from server to server. It is one of the criteria you'd look at for choosing a server.

Likewise local community is another, if you should care. There is a special Local feed, which i've found to be quite handy if the server you're on is specialized to a content type.

As for choosing your server, i think the above two points are useful metrics to help you decide. However if you're just looking to dip your toes in, pick any server. You can always decide to switch later, as you can set your old account to indicate that you moved to a different account. I've seen several accounts like this and it seems to be sane and easy.

So far i've been quite happy with Mastodon.