Twitter's latest transparency report, covering the second half of 2012, reveals that US authorities are filing an increasing number of user information requests.
A total of 815 requests were made in the second half of 2012 and 1145 user accounts were specified. The vast majority of the requests came in the form of subpoenas, as many as 60 percent. Court orders accounted for 11 percent, while 19 percent of the requests were made through search warrants.
Twitter notes that subpoenas generally do not require a judge's sign-off and usually seek basic subscriber information, such as the email address associated with the account and IP logs. Court orders are a bit different, in that they must be issued by an appropriate court and signed by a judge. Search warrants are reserved for more serious infractions, as they require the most judicial scrutiny, including proof of probable cause and a judge's signature. A search warrant is required for the disclosure of the contents of communications, such as Tweets and messages.
About 10 percent of the requests do not file in any of the above categories and most of them are emergency disclosure requests and other requests for user information without a valid legal process.
Twitter's policy is to notify users of the requests, but in some cases Twitter is prohibited from making such notifications. About 20 percent of the requests were issued under seal, where Twitter is directly prohibited from notifying the affected persons and third parties. Here is another interesting statistic: 56 of the requests were not sealed, but the users were not notified because the requests were withdrawn, defective or they were emergency disclosure requests.
Just 24 percent of Twitter users were actually notified by Twitter, and the notification included a copy of the legal process.