This is a recent article in the Wall Street Journal, about federal investigators examining whether certain app makers clearly described to the users the different kinds of data they were collecting and why they were collecting it.
Data here in terms of apps relates to the geo location of the phone as well as unique identifier information (for example- age, gender and other personal details).
In short these apps, did not have a clear cut privacy policy. The more we move into a networked age where technology flows seamlessly in between web tools, tech gadgets, applications, utilities, crowd sourced knowledge and other 2.0 tools, the more essential it is for each app, tool, website, service etc to have their own individually crafted privacy policies which are updated regularly.