Q: How does this work?
A: Incoming mail is never logged, encrypted--whilst never being stored on any storage medium (ssd, hdd, etc') and then forwarded to your email of choice where you can then unencrypt it with your private key. Accounts are based off of pgp public keys, there are no passwords, email content is encrypted based off of your provided public key.
Q: How do I acquire an invite to this service?
A: Currently, this service is invite-only. There is no way to get an invite besides being given one by an administrator.