In the wake of revelations that the Obama administration is tracking virtually every single phone call of every single American, the administration has trotted out an unsurprising defense: we're not listening to your phone calls, just snatching the metadata!

What is metadata? My colleagues Ben Wizner and Jay Stanley explained it well in this op-ed .

But don't take our word on how sensitive metadata is. Here's then–Senator Joe Biden, in a clip featured on The Daily Show Monday night, criticizing a similar call record-collection program revealed in 2006 under the Bush administration, and explaining how studying your call habits can be "very, very intrusive":

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How intrusive is it for the government to collect all of your metadata, for years at a time? Just like Biden says, it's incredibly intrusive. Often the government can learn just as much about you by analyzing whom you're calling, when, and from where, as by actually listening in. As Ben and Jay explained in their op-ed: "If a politician were revealed to have repeatedly called a phone sex hotline after 2:00 a.m., no one would need to know what was said on the call before drawing conclusions."

Click here for more updates and analysis on the NSA surveillance program.