Anyone can set up and run their own server on here.
This is great for lots of reasons (outlined here: https://fedi.tips/why-is-the-fediverse-on-so-many-separate-servers/) but it also means that a small minority of servers may be run by nasty people, and potentially contain nasty content.
Fortunately, most server admins use server blocks to prevent their users having any contact with rogue servers.
If you see something bad on here, it's important to report it so that your admin can take action. Click on ⋯ and "report" to report a post.
p.s. If you're interested in setting up your own server, you don't need to be technical or rich. It can be done through "managed hosting" services which handle all the technical stuff on your behalf, and starts from about $10 a month for a small server.
I run a website all about using managed hosting at https://growyourown.services/grow-your-own-social-network/ and it includes a step-by-step non-technical guide to making your own Mastodon server at https://growyourown.services/making-your-own-mastodon-server-in-10-steps/
@feditips I'd be really interested in deploying my own instance. However, one thing I was wondering about was the whole legal aspect of it. Like would I be responsible for everything the users post? I feel like proper moderation is bound to become increasingly difficult with rising numbers of users.
I am not a lawyer, but it's my understanding that the legal position depends on where you live. In some countries you may be responsible for everything they post.
It's probably better to start with a single person server to get used to the idea, then see how you feel. Some people open it just to friends, and others open it just to small numbers of strangers. Whatever you do, moderation will always be easier on smaller servers.