It’s difficult to have an informed opinion about the National Security Agency’s collection of “metadata” without understanding what “metadata” is, not that that’s stopped anyone. The name suggests that it’s data about data, and the Obama administration has gone to some lengths to reassure Americans that “metadata” is definitely not “content,” which unlike your “metadata” presumably enjoys Fourth Amendment protections. But Glenn Greenwald, among others, has said that’s a distinction without a difference: “In reality, it is hard to distinguish email metadata from email content.”

For anyone still in the dark — pretty much everyone? — there’s a simple way to figure out what the N.S.A. can glean from your email: An online program from the MIT Media Lab called “Immersion.”

The Boston Globe wrote about it last week:



“[Immersion] asks users for their Gmail address and password; it then scans every e-mail in their accounts and scrapes the metadata to create a portrait of their personal network. With the circles and lines of a network diagram, it highlights the 100 people with whom you’ve communicated most, and shows how closely they’re connected to you and how thickly interconnected with one another in your mailbox.”

Yes, it only works with Gmail and you have to reveal your password. But as The Boston Globe notes, “Unlike Google, or the NSA, the project also offers an instant deletion option: Remove your name, and it erases your metadata.”

Sign up here: https://immersion.media.mit.edu/

If you send yourself emails from your work or school or other personal accounts, Immersion will be able to assemble a list of your email aliases. That means anyone looking at your metadata could figure out where you’ve worked and where you attended school. (e.g. that I used to work at Slate, because I had a Slate email account.)

The program can figure out how many emails you’ve sent, to how many people, and who you’ve emailed the most in the past month, year or overall. It knows when you first emailed a given contact, and the last time you emailed him. It can guess which of your contacts know each other, and even how you got to know certain people. (e.g. it gathered that my husband introduced me to his mother and brother and college friends.)

Here’s a screenshot of my network, scrubbed of identifying information. The largest circle represents my husband: My “top collaborator.”