So here's the scary number: the major wireless carriers (Verizon, AT&T, Sprint, T-Mobile, and a couple little guys like U.S. Cellular and Cricket) revealed that in total, in 2011, they received 1.3 million requests for user data from law enforcement agencies. They released this information only after an inquiry by Congressman Edward J. Markey. This is the first time we've had any overarching glimpse at how (and how often) the carriers work with law enforcement.
This is a major step forward towards transparency. It received a front-page New York Times story, and certainly a fair bit of coverage elsewhere. It provides much more information than we've ever had before, especially from AT&T, which lists a few categories of requests as well as the specific (very tiny) number of requests AT&T refused to honor. But! That 1.3 million number leaves out some legitimately important information. Most important: what information is revealed, exactly, and how often do the carriers comply?