Cryptpad
CryptPad encrypts changes to pads before sending that information to be stored on the server, so the provider can't read the content, unless somebody knows the URL.
Cryptpad is advancing https://blog.cryptpad.fr/2017/08/18/CryptPad-s-New-Direction/
board.net's etherpad instance is growing and there is currently no policy for deletion or quota, which cryptpad has.