PrivateSky is a browser based encrypted messaging and managed file transfer service. The keys are only available to the sender and recipient, not even CertiVox staff can access the keys. They are not physically able to comply with CALEA requests, as all encryption and decryption happens in the browser.
Sign up for the service, it's free. The service is served over SSL so there is little risk of MITM (that would require a Diginotar style hack). The marketing site does not require SSL. We are not collecting and you are not transmitting any information on the marketing site (except for Google Analytics). The domain is registered at GoDaddy. Yes, we are not big fans of GoDaddy, but it's a pain to move your domain registrations. The domain proxy service is standard when you don't want to receive a lot domain spam to your technical contact.