in addition to cryptographically signing this note with his private key, he also used his computer to do a small amount of 'Proof Of Work' which depending on his purposes (maybe a relay he uses requires it to store the note longer term; or some other reason) he believes there is some benefit in doing it.
I hadn't heard of this. How do you do it?
I am not sure if it is doable on #amethyst. some clients have it and some do not. I believe Odell uses Gossip client for desktop.
getwired.app uses PoW21 for all posts, and acts as an anonymous posting client.