I think semi public would be like setting your facebook profile to private. It shows your name, and basic details, but doesn’t show all your posts or interactions.

Seems reasonable. It's good to figure these things out now btw, as courts will adopt the "common definition" if the law doesn't explicitly define things (including referencing dictionaries for the meanings of words).

I find this interesting. Does one just install software and buy a domain?

You don't even need to buy a domain necessarily, just have a place to install the software and use one of the free services.

I run my own self-hosted single-user pyfedi instance, and I more-or-less do so for free (I mean I pay for internet and I bought the old laptop that I'm running pyfedi on ages ago, but that's it).

After looking at a lot of different options, I decided to go with srv dot us since srv dot us guarantees you a permanent domain name without having to pay (albeit you can't pick the name). srv dot us actually doesn't require any signup either - you just follow the instructions, connect, and go - and they only keep records like your ip address for one day, so if you stop using it for longer then poof you're suddenly that much harder to trace.

ngrok dot com also offers a free domain name (but you can't pick - if you want to choose your own then you have to pay). You sign up with your email and all that though (you can also sign up using your github account). I almost went with this (the author of pyfedi, Rimu@piefed.social , mentions (recommends?) using ngrok for this purpose) but at the time I had some other issues and misdiagnosed it as ngrok blocking federation with their silly popup (see https://stackoverflow.com/questions/73017353/how-to-bypass-ngrok-browser-warning for more details)

You can learn more about pyfedi by visiting the flagship instance at piefed.social

I would assume theres somewhere you have to register with in order to federate.

Nope, nothing like that. Verification is done mostly just by making sure you own or otherwise legitimately have access to the domain that you are using (specifically that you have SSL certs that are certified for the given domain for use in HTTPS if you wanna get a little bit technical).

I mean, if theres no one to go after, this would be a nice work around. At least, until theres a site for every Texan that figures it out.

So fly-by-night instances it is! It wouldn't necessarily work for large instances with many users though - pretty much all of these do buy their own domain, for which you have to provide your legal name and address and such (even if it's not public thanks to domain privacy, it would be available to law enforcement)

And federation does not play nice with someone's domain name changing. Meanwhile if one is caught registering for a domain with a fake name etc then the domain registrar is entitled to cancel the ownership of that domain and take it back.

That said, one might luck out and find a good domain with a registrar that's in a jurisdiction that is particularly unfriendly to Texas's ability to enforce SCOPE.

Edit: haha, you kinda answered this somewhere else as I was typing

Thought I could enhance my previous answers by adding a little more detail here.