Yeah, sounds great in the first place, but then again you’d have to consider how one would implement such a list without the need of registering an account or something of that sort.

My friends and I are basically sharing our followings publicly in a separate text file next to the main one, so we can discover new people.

Not sure I'd want to be in a directory, but wouldn't mind if someone queried based on my email address.

How about a DHT where sha160(emailaddress) would return the URL I use. Could even use the mainline torrent DHT.

Brute-forcing email addresses doesn't seem particularly hard, and a mechanism like that would then allow checking for email address validity and corresponding URL.

How would you prevent people from registering email addresses they don't own?

I like this too, but it is pretty hard to use without a directory, so I created a simple one here where you can register your username: http://twtxt.reednj.com

Just improvised something (probably temporary) here: http://test.plomlompom.com/twtxt/account_list.txt

Why not try https://twtxtlist.cf/?