As someone who follows the government's ravenous appetite for data collection and mining - I feel it's important to remember that the NSA's warrentless wiretapping program, (and any other classified programs Gonzales may or may not have referred to in his Congressional testimony) is not the only instance of our government pushing data-mining technology.
First, start with the NSA wiretapping program that permits our government to freely analyze and listen in to the communications of folks on American soil chatting with folks overseas.
Add to that the recent news about the FBI's 2008 proposed budget item for Communications Exploitation, including funds for a Telecommunications Data Collection Center, which would partner with three of our nation's telecoms to:
provide access to land-line phone call, calling card, cellular phone call, and internet communications records, all delivered in an electronic format that can be exploited immediately to help resolve terrorist threats.
(Thanks to Threat Level for posting the budget proposal, and check out Ryan Singel's coverage on this).
Starting next year, if we fly from Europe to the U.S., airlines have to give our info to the Department of Homeland Security, who will keep the records for 15 years. According to The Washington Post, sensitive personal information may also be accessed in "exceptional cases:"
According to the deal, the information that can be used in such exceptional circumstances includes "racial or ethnic origin, political opinions, religious or philosophical beliefs, trade union membership" and data about an individual's health, traveling partners and sexual orientation.
So the government appears to be either outright asking for its own duplicate copy of our data, or is paying companies to keep the warehouse the data for them.
And if the government automatically receives a copy of our information, it doesn't need to present a warrant or court-order to the internet provider/airline/phone company every time it wants to access and analyze someone's information. Law enforcement would have its own duplicate copy to mine without having to prove probable cause. Finally we have to realize that we have absolutely no idea what the NSA is doing with all this information, except that it goes far beyond just listening to phone calls.
That, my friends, is a problem.