Rep. Edward Markey, D-Massachusetts, and Rep. Joe Barton, R-Texas, sent the bipartisan request Wednesday with a deadline: Zuckerberg has 15 business days to cough up the answers.
The congressmen's intrigue centers on Facebook's recent announcement - and postponement - of a plan to make the addresses and cell phone numbers of its users available to third-party websites and application developers (apps).
"Please explain why Facebook, while previously acknowledging in its letter to us that sharing a [Facebook User ID] could raise user concerns, subsequently considered sharing of a user's home address and mobile phone number - even more sensitive personal information than a UID - to be information that should be more easily accessible to third parties," they wrote in the letter.
They further take Zuckerberg to task writing, "Facebook initially announced the new feature in a blog post meant for developers. Does Facebook consider that prominent notice to users? If not, please describe how Facebook intended to notify users of this new feature."
The query includes 11 questions and four sub-questions that probe the Facebook founder on whether the social networking site has considered the risks to children and teenagers as a result of the new policy, why the policy is needed, and why it was subsequently delayed.
Markey and Barton sent a similar letter to Zuckerberg in October 2010 which sought answers on reported "privacy breaches." Zuckerberg responded two days after their requested nine-business-day deadline.