Rep. Henry A. Waxman, D-Calif., and G.K. Butterfield, D-N.C., publicized the letters on Thursday, one of which was addressed to Apple Chief Executive Tim Cook for its "Find My Friends" application.
Letters were also addressed to Mark Zuckerberg of Facebook, Dick Costolo of Twitter, Jeff Weiner of LinkedIn, Alexander Ljung of SoundCloud, Dennis Crowley of Foursquare, and Bill Chasen of Turntable.fm.
The companies are being questioned because of recent concerns over developers having access to a user's address book stored on their iOS device. The congressmen seek to better understand what information the applications gather, what they do with it, and what notice is provided to users.
The developers targeted in the inquiry were selected because their software was found in the "Social Networking" subcategory on the "iPhone Essentials" curated list of App Store software.
Another major inclusion on the list is Dave Morin of Path, the company that arguably started the iOS address book controversy. Path and Morin came under fire in February after a developer discovered the application was uploading data behind the scenes without notifying users.
Last week, it was said that Cook himself "grilled" Morin after he learned that the "Path" application was uploading users' address books to its servers without their permission. Morin allegedly took part in a meeting with Cook held at Apple's Cupertino, Calif., headquarters.
Butterfield and Waxman already sent a letter to Apple in February seeking information about iOS address book security. They questioned whether Apple's application developer policies and practices adequately protect consumer privacy.
Apple distanced itself from the controversy by stating that applications that collect or transmit personal information without first obtaining permission are in violation of its developer guidelines. The company has promised to require explicit user approval before App Store software can access contact data in a future iOS software release.
[ View article on AppleInsider ]