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.

Why is the Fediverse on so many separate servers? | Fedi.Tips – An Unofficial Guide to Mastodon and the Fediverse

An unofficial guide to using Mastodon and the Fediverse

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/

Grow your own social network – Grow Your Own Services

@feditips

Interesting: $10/month is exactly what I contribute to my current instance, since the volunteers there take care of all the upkeep and maintenance.