At the end of 2006, the FBI's Telecommunications Intercept and Collection Technology Unit compiled an end-of-the-year report touting its accomplishments to management, a report that was recently unearthed via an open government request from the Electronic Frontier Foundation.

Strikingly, the report said that the FBI's software for recording telephone surveillance of suspected spies and terrorists intercepted 27,728,675 sessions.

Twenty-seven million is a staggering number given that the FBI only got 2,176 FISA court orders in 2006 from a secret spy court using the Foreign Intelligence Surveillance Act.

According to the math that means each court order resulted in 12,742 "sessions," all in regards to phone, not internet, surveillance.

FISA watchers have long wondered whether FISA warrants covered more than one person. Knowing how many calls or text messages the FBI captured could add a piece to the puzzle.

Unfortunately, nothing in the documents turned over yet to the Electronic Frontier Foundation explain what a session is. Does it refer to one session of listening in on a target's conversation, even if it is minimized for not being relevant? Does it include text messages? Does the incoming call number and the recording of the call count as two sessions? Do cell phone pings that reveal the general location of a target count as a session? Unknown.

Steven Aftergood, who runs Secrecy News for the Federation of American Scientists, says it's an odd, and not so useful statistic:

I've never seen a number like that. When I hear 27 million sessions that sounds like they are talking about individual communications that were monitored for each individual target.

Aftergood thinks that if you take the number of targets and add them up, it's not that crazy a number. He also suspects that there are likely less than 2,100 foreign surveillance targets and that each target likely gets multiple orders - one for a fax line, one for a cell phone, one for a secret house search, etc.

It's a surprising statistic to keep because it doesn't tell you much. What you want to know is how many of the foreign intelligence surveillance sessions were of significance. If only three out of 27 million were useful, that would tell you something, but one number without the other is meaningless.

Of note is that the software at issue, the DCS-5000 gets information from carriers after they turn on surveillance on their switches once they get a court order (CALEA mandates the switches be wiretap-compliant). That means this number ostensibly has nothing to do with the government's secret warrantless wiretapping program, or the government's data-mining of billions of call records.

See the 27 million figure here (.pdf) (p. 35) and drop your reasoned or snarky hypotheses in the comments.

Check Wired.com Wednesday evening for a fuller story on the Freedom Of Information Act-obtained documents.

For a primer on the FBI's Digital Collection System and how it works with wiretap-friendly telecom switches, check this August story: Point, Click ... Eavesdrop: How the FBI Wiretap Net Operates

Colored photo-illustration: Frank Rodriguez