A journalist makes a phone call from their mobile phone to their editor in London. They utter a single word that lights up a light on the screen of a security service’s operative. 24 hours later they’re dead.

It’s a scene from The Bourne Ultimatum, and it makes you wonder just how much your usage of mobile devices can reveal about you. It’s fiction… of course. But like all good fiction it’s grounded in reality. Your mobile could be revealing much more about you than you might think: things about your personality, your habits, your movements, your social network, who you meet and when….

I came across and article about Reality Mining, the natural extension of Data Mining, over on the Technology Review website. It cites MIT professor Sandy Pentland, who believes that the increasing sophistication, penetration and connectivity of mobile devices is about to herald a new era of analysing and predicting human behaviour based on the data mobile operators collect about us.

According to Professor Pentland, Reality mining… “is all about paying attention to patterns in life and using that information to help [with] things like setting privacy patterns, sharing things with people, notifying people–basically, to help you live your life.”

Add in the fact that mobile devices are increasingly location aware, and are becoming powerful computers in their own right, and, in theory, the data gleaned from these devices could be used to personalize the information, services, and of course advertising, that we receive in a way that’s simply unprecedented.

But it raises the age old question — just because we can, does that necessarily mean that we should?

Last May, according to the Technology Review article, Pentland and his team demonstrated how cell-phone data enabled them to accurately model the social networks of about 100 MIT students and professors. They even managed to predict where subjects would meet with members of their networks on any given day of the week. Powerful… useful… and potentially very intrusive stuff!

But it goes much further than that — data from cell phones could, for example, be used to augment models that predict the spread of contagious diseases, adding data about social relationships into the modelling algorithms. Or perhaps to flag the onset of depression — because a phone could, apparently, pick up the cues more readily than friends or family. Exciting, but at the same time I find it more than a little disturbing.

For marketers, of course, being able to track and predict the behaviour and social interaction of prospects opens up all kinds of doors. It could also open up an enormous can of worms.

“All of the devices that we have are completely ignorant of the things that matter most,” says Pentland. “They may know all sorts of stuff about Web pages and phone numbers. But at the end of the day, we live to interact with other people. Now, with reality mining, you can see how that happens … it’s an interesting God’s-eye view.”

The problem is, I’m not so sure I want people to have a “God’s eye view” of how I interact with other people… however enticing it might be from a marketing perspective. How about you?