Game Making Toolts is a user on You can follow them or interact with them if you have an account anywhere in the fediverse. If you don't, you can sign up here.
Game Making Toolts @gamemakingtools

In light of improvements to what Mastodon does with them I've enabled invites for all users.

So you can invite a friend directly to an instance to make signing up less intimidating for new people.

Better info in this post on the new Mastodon blog: