What about keybase.io?
Originally created by @jvoisin on #11615 (Redmine)
keybase is a website to map keys to identities
and vice-versa.
Long story short, you sign a message with your gpg key, put it in a
tweet or in a keybase.txt file, or in
a super-small bitcoin transaction, and keybase will show all those
relationship on its website, but you don’t have to trust it, you can
verify those proofs by yourself, since the files are public.
This would help people to verify that the bitcoin address, the website and the twitter account are controlled by Tails. It will also show that the people twitter account, the website and the BTC address are controlled/endorsed by the people behind the gpg key.
The only maintenance needed is to update the messages upon a key rotation/change.