It's easy to miss and it's been getting lost in all the noise, I fear. You don't appeal subpoenas, you try to quash them and prevent the information from being disclosed to begin with. I mean, you can't very well have them un-share your identity or personal information after the fact any more than you can un-ring a bell.
Here's one nice little article about how they work in practice:
You will note that they commend Twitter for giving the user notice of the subpoena, even though Twitter is not required to. That's an important point, too: companies may go above and beyond what they're required to. So, assuming you use services that do that, you might get notice even when the company wasn't legally required to provide it.
Finally, here's the Justice Department's own report to Congress on the use of administrative subpoenas:
Here's one nice little article about how they work in practice:
http://privacysos.org/admin_subpoenas
You will note that they commend Twitter for giving the user notice of the subpoena, even though Twitter is not required to. That's an important point, too: companies may go above and beyond what they're required to. So, assuming you use services that do that, you might get notice even when the company wasn't legally required to provide it.
Finally, here's the Justice Department's own report to Congress on the use of administrative subpoenas:
http://www.justice.gov/archive/olp/rpt_to_congress.htm
Appendix A1 is probably the most relevant part of that, specifically the column labelled "Notification Req. and Privacy Protections."