private twetch accounts: accts where twetch does not have t…

private twetch accounts: accts where twetch does not have the decryption key for a user, but whenever a user receives a "follow request" that user is approvied individually in order to receive the decryption keys. Having 10 users in mutually private accounts means that each user has approved each other. It also means that there would be a decryption key for each message as well as other user (every post generates X decryption keys which can then be revoked) which allows messages to be deleted for some recepients and not all. i expect that this is exactly how chat works, which means chats with tens or hundreds of users produce high server costs unless the work is outsourced to browsers...