According to an WSJ article, Apple and Google didn't realize the values in this gigantic pool of data until recently. There is also the recent discovery that social networking and behavioral data can be automatically logged by our cell phones. The use of the data? Better marketing. In a recent article by WSJ, it is pointed out that our phone can actually log our body language during phone calls, the same technology that has made our iphone games more fun. Therefore, statistical methods can (potentially) be applied to study the association between body language and the content of phone calls. A always walks around while calling B, and sits at a desk while calling C. Different social ties, possibly different social influence, and thus different marketing values. Existing research has already achieved a level where a trained learning method can predict whether two people are discussing politics without actually logging the conversation. This prediction was based on some call history, location, timing of the call, etc.
This seems to suggest a new wave of interesting data, gigantic in size and complex in nature, attractive to both machine/statistical learning researchers and social/behavioral researchers.
PS: Michael Malecki posted the R codes he used to analyze his own iphone data. I can't wait, but yet to find time, to try this on my own iphone data.