What is different about the government logging traffic between Lavabit and the user versus the SMTP between another host and Lavabit? With Lavabit's key, they

What is different about the government logging traffic between Lavabit and the user versus the SMTP between another host and Lavabit? With Lavabit's key, they can get all incoming mail (and many providers don't even use STARTTLS). Perhaps their logged traffic was incomplete or is difficult to search? Email just isn't very secure as a protocol; people that care need something they can verify, like PGP (which Snowden used). It's unfortunate that the asynchronous nature of email (which we tend to view as an important feature) is incompatible with client-verifiable forward secrecy.