In case you haven't been following this case, Lavabit is (or was) a secure e-mail service. All mail is encrypted so no unwanted third parties (not even Lavabit) can snoop the content. The US government didn't like the idea of an e-mail service they couldn't spy on so they sent him threatening letters demanding access. According to the above linked articles, they wanted a full tap into the content of all messages from all users. Rather than comply with this blatantly unconstitutional abuse of power, the owner shut down the service.
And now the Feds are threatening to prosecute him for doing that!
I'm sure my left-wing friends will see no problem with this, but for the rest of us, this is just another example of the abusive totalitarian nature of the US government today.