Eugen is a user on mastodon.social. 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.
If you have a mastodon.social account but have moved over to a different server, you can login to your old account and, under edit profile, setup a profile redirect note.
@Gargron Thanks for the tip, I just did so. I can't get my head around to what that actually DOES, though ...
@Gargron So nothing actually happens with my account on mastodon.social anymore? If anyone tries to contact me on .social they just get a message that I moved ?