In the beginning of August, Ladar Levison shut down his Lavabit email service without warning, citing the reasons as being related to the government and a requirement that would make him "complicit in crimes against the American people." The case has been sealed and Levison is under gag order, greatly limiting any details he can provide on what went down. That may change soon, with Lavabit requesting a partial unsealing so that others can file amicus briefs.
An amicus brief can be submitted by those who aren't directly involved in a case, but who have interest in it for various reasons. Under a court document that has surfaced showing a request to have the case unsealed, we see that appellants (who have been censored) "state the following in support of their motion to unseal the case, or in the alternative, for a protective order to allow potential amici curiae to view documents currently under seal that are the basis for this appeal."
Such is necessary because amicus briefs cannot be submitted if the case is sealed and the entire process is taking place via a so-called secret court with little oversight. The information involved, however, is important to citizens and would shed light on what the government is doing behind closed doors in relation to private data and spying. If the case is unsealed so that amicus briefs can be submitted, all will get a look into what exactly prompted Lavabit's closure.
On August 13, the service's founder spoke up about the matter, and though he didn't (and still can't) divulge details without risking running afoul of the law, he did say this: "I think that if the American people knew what our government was doing, they wouldn't be allowed to do it anymore. My hope is that the media can uncover what's going on without my assistance."