Representatives Henry Waxman (D-CA) and Fred Upton (R-MI) sent letters to Apple and 33 iOS app developers today, requesting detailed information about their data collection practices. On March 2nd, The House Energy and Commerce committee sent a letter to Tim Cook saying that Apple did "not answer a number of the questions we raised about the company's efforts to protect the privacy and security" of its users, and requested that Apple send representatives to brief its staff. Now, the committee has expanded its investigation to 34 developers, including Twitter, Turntable, Foursquare, Facebook, and Path, and says it wants "to better understand what, if any, information these particular apps gather, what they do with it, and what notice they provide to app users." If you'll recall, the app privacy issue started with a firestorm over Path's use of address book data back in February, after which a brood of similar privacy accusations swarmed upon Apple and other developers.

In the letter, the members ask how many times the developer's app has been downloaded, when and how its privacy policy was administered, whether the app transmitted or stored address book or other information from users, how notices about collection and use of user data are transmitted -- questions similar to the ones in the committee's earlier letter to Apple. Congress has asked the recipients to respond by April 12th, and depending on how satisfied the committee is with this round of questioning, the matter could be taken up in a congressional hearing — the committee certainly seems interested enough in the issue to talk it out in public.