farcaster network + prove.email = permissionless blind

would be cool to see forums gated by zkp credentials

prove your employer with a ZKP over a recently received email on your work address, exposing only the sender (the company email). 

Prevent sybil issues with a sign-up fee

The part I'm missing is the encrypted groupchat piece once you've proven your membership

Yeah! Nozee is testing this right now with nozee.xyz; no sign up fee since I think it's a bit user hostile, but you use ECDSA keys to post so you can made shared ECDH keys for encrypted comms