We did organise the 8th edition of our Workshop for Management of Ubiquitous Communications and Services (MUCS) at PerCom. The most interesting session was a keynote by John Krumm, Senior Researcher from Microsoft Research. They did collect 100 Million GPS points in Seattle, and then did a lot of analysis with that information. From predicting routes of people, to looking into where they are over a period of time (day, week, month) to how much noise is needed to hide locations. They also did a questionnaire with their volunteers to see when and for what incentive they would give away data about their travelling.
A lot of the information from the keynote is in John’s papers and presentation, which can be found at his website. He also has slides from a very similar keynote talk available here. And if you want to play with the data yourself, he even published parts of the set of 100 Million GPS Points.