Looking for an intuitive way to understand the kind of data the N.S.A. has been collecting on all of us? A team at MIT has developed a helpful graphic for GMail users. Immersion is a program that reads only the meta data from your email - precisely what the N.S.A. is collecting from telephone and internet records - and creates a visual web of interconnectedness between you and the people in your inbox.

What's the big deal about collecting this information? If you're of the mind to give Immersion a try, you can get a sense of the kind of information it can reveal, particularly over time. According to The New Yorker's Jane Mayer, you don't need to know the content of conversations to get the gist of what's going on. Mayer's post points out that you might make an appointment with a gynecologist, then an oncologist, and then you may make a series of calls to close family members and friends. What's going on? It's not hard to deduce that you've received a diagnosis of cancer. Likewise, journalists who count on anonymity to protect their sensitive sources can be outed easily with meta data. And lest you think you are carrying on an extramarital fling unnoticed, meta data can reveal that, too.

This type of intrusion is easy to minimize because meta data is not meaningful or even familiar to most people. Intuitively, we are more concerned with revealing the content of our conversations. Yet if we are to fully understand the significance of this type of data mining, we must present the data in ways that hit home. Immersion is one such way. Check it out.