I don't understand the outrage here, aren't gag orders pretty much standard police tool? I mean, if you are taping the new Al Capone/Ben Laden/Ted Bundy, then surely you don't want Twitter to reveal it no?
It would make no sense to let the provider say "we're monitoring Al Capone", as this would alert Al Capone. But they're not even allowing the provider to say "certain users are subject to wiretapping at government order". On a huge service like Twitter this would not alert anyone in particular.
Even the above is not as much of a concern - but the same mechanism can silence the providere about more drastic intrusions which compromise the whole service - such as coercing private encryption keys. Lookup the whole Lavabit thing.
