We're working on a solution for user to link their Fb/twitter identity to a decentralized ID and post encrypted post/comment (even sending any crypto over) on Fb/twitter only viewable by friends *(not able to decrypted by Fb or NSA) -

https://maskbook.com

Source code:

https://github.com/DimensionDev/Maskbook

For now we're trying to integrate decentralized FS solution as well so eventually Fb/twitter can be merely an infrastructure layer