More than a dozen privacy and consumer protection groups have banded together to protest what they see as duplicity by Facebook when it comes to safeguarding people's information.
The Electronic Privacy Information Center said Thursday it had joined 14 other organizations in filing a complaint with the Federal Trade Commission charging the social networking website with "unfair and deceptive" practices.
The cadre of Facebook critics also fired off a letter to the US Congress urging legislators to closely monitor how the commission looks into Facebook privacy concerns.
"The company has done this repeatedly and users are becoming increasingly angry and frustrated," the missive continued.
The complaint accuses Facebook of violating consumer protection law with information handling changes that "violate user expectations, diminish user privacy, and contradict Facebook’s own representations."
The social networking site on April 21 rolled out a series of new features including the ability for partner websites to incorporate Facebook data, a move that would further expand the network's presence on the Internet.
Last week, four US senators expressed concern that changes to the social network compromise the privacy of its more than 400 million users.
In a letter to Facebook co-founder Mark Zuckerberg, the senators said they worried that personal information about Facebook users is being made available to third party websites.
They also said the Palo Alto, California-based company should make sharing personal information an "opt-in" procedure in which a user specifically gives permission for data to be shared.
One of the letter's signatories, Democratic Senator Charles Schumer, has urged the FTC to look into the privacy practices of Facebook, MySpace, Twitter and other social networking sites and to issue guidelines on the use of private information.
The complaint by privacy groups was filed on Wednesday, the same day Facebook temporarily shut down its online chat feature after a software glitch let people's friends in the online community see each others' private chat messages.
The problem was quickly fixed.
Facebook vice president of global communications Elliot Schrage has been adamant that online privacy is taken very seriously at the company.
"These new products and features are designed to enhance personalization and promote social activity across the Internet while continuing to give users unprecedented control over what information they share, when they want to share it, and with whom," Schrage said.
Explore further: Facebook glitch exposes chat messages (Update 2)