Lavabit, an encrypted email provider that was implicated in Edward Snowden's leak of controversial NSA surveillance, chose to shut down its service in order to avoid government demands for its data. Silent Circle, a similar private email system, did the same. Now these two entities have got together to form what they're calling the Dark Mail alliance, and this time they're serious about preventing surveillance of email discussions.
The Dark Mail plan is to not only provide peer-to-peer encrypted email messages, but also to encrypt the metadata of those messages too, to try to make sure it will be hard for anyone other than the intended recipient to read the messages. Presumably it's also useful to encrypt "from" and "to" components of the email so that there's no useful user data on the company's servers that a government body could try to access.
Dark Mail's products will be downloadable in 2014, but they will certainly remain controversial from this point on.