As crappy as this is - it seems to be legal and logical. You don't get to claim privacy on something you're broadcasting to the world, and neither does the company, considering they asked LoC to permanently archive a chunk.
As approximately half the comments in this thread are currently at pains to point out:
It is not surprising that something which is broadcast publicly is public.
It is very, very surprising that the public nature of anonymously-published material is in any way relevant to whether the private identity of the author should be disclosed.
Did you read the article? Twitter was arguing that the subpoena was incorrectly issued in the first place, not they are somehow above the law.
The subpoena was based on rules that assume that the twitter user's email address and direct messages (like public tweets) are already public. This is surprising since I think most Twitter users would agree that those things aren't expected to be public.
No. I'm pretty sure the subpoena was for _public_ tweets and personal identifiable information (ip address, email, ...).
I think you are confusing personal identifiable information with direct messages. The direct messages _do_ have an expectation of privacy around them, but that information was never requested.
Logical only if you follow the analogy of screaming out of a window. It's a smart analogy because superficially it seems identical.
The tweeters in Tahrir square however would have got killed had they screamed out of a window. Twitter gave them a public forum and anonimity. A completely novel concept, and one that deserves a more careful ruling than this brash analogy.
It's the same simpleton internet to real world translation the MPA/RIAA use to equate "file sharing" to physical theft. It's an easy analogy to pull the wool over the eyes of less technically inclined individuals.
