Twitter said Monday that just 19 percent of federal and state government requests for user data were accompanied by probable-cause search warrants during the six months ending in December 2012.

In all, the San Francisco-based micro-blogging service, in its second so-called transparency report, said there were 815 demands for Twitter account-holder data. Twitter did not say what type of user data was sought in those 815 requests, but it likely includes a mixture of e-mail addresses associated with accounts, IP logs, tweets and direct messages.

Twitter did not say what data it hands over. But it said it demanded a probable-cause warrant for tweets and direct messages – although the courts don't always see it that way.

The disclosure came a week after Google and Yahoo told Wired that it requires probable-cause warrants to divulge to the authorities e-mail and cloud-stored content of its account holders, despite federal law not always demanding that.

Twitter said it complied with subpoenas, court orders and probable-cause search warrants 69 percent of the time in the latest reporting period.

Previously, Twitter reported that it complied with 75 percent of the 679 demands in the first half of 2012. In that original transparency report, Twitter did not chronicle what legal tools the government used to acquire user data.

To be sure, Twitter indeed fights for the privacy of its account holders, despite it sometimes being a losing battle.

Last year, for example, it was forced against its wishes to divulge the tweets and account information associated with the account of Malcolm Harris, who was arrested in an October Occupy movement march along the Brooklyn Bridge. Twitter fought for Harris, but in the end lost, even though no probable-cause warrant was used by New York state prosecutors.

Twitter also said it notifies its users about requests for data "unless we are prohibited from doing so by law or in an emergency situation." In all, Twitter said 24 percent of all requests "resulted in notice to affected users."

Worldwide, 81 percent of all requests for user data originated in the United States, Twitter said.

Meantime, the company said it received 3,268 notices to remove content under the Digital Millennium Copyright Act in the latest six-month reporting period, compared to 3,378 the previous six months.

Homepage photo: Scott Beale / Laughing Squid