Currently user notebooks are located under the observablehq.com domain. I have a use case which would warrant a subdomain. Specifically my notebooks are frequently viewed by users using the Brave browser which has a feature that allows users to tip sites. In order to do so the publisher of the content needs to register the site with BAT and verify through the domain they registered.
There maybe another solution here, which is observablehq.com is the top level registration and splits the tips with owners of the particular notebooks that has been tipped.
I briefly looked into this, and set up tipping for my personal website (and earned nearly 25 cents), but it looks like we’d need a bit more than domains for this. Personal notebooks already do run on subdomains, albeit in the iframe: your notebooks run under https://bgits.static.observableusercontent.com/ and mine run under https://tmcw.static.observableusercontent.com/
That said, to configure BAT-getting, you need to either configure DNS settings, or to upload a .well-known/brave-rewards-verification.txt file to the subdomain.
So it’s possibly something that we can configure down the line, assuming that Brave allows tipping in iframes, but we’d need to do this specifically for Brave - just adding per-user subdomains won’t do the trick. We’ll keep it in mind.