Facebook on Friday blasted employers that want to peer at what workers have posted on their personal accounts at the world's leading social network.

Facebook chief privacy officer Erin Egan urged members of the online community not to share passwords with current or potential employers and warned companies to resist pressing for access.

"In recent months we've seen a distressing increase in reports of employers or others seeking to gain inappropriate access to people's Facebook profiles or private information," Egan said in a blog post.

"The most alarming of these practices is the reported incidences of employers asking prospective or actual employees to reveal their passwords."

She argued that snooping employers undermine the privacy of workers, and their friends at Facebook, while exposing themselves to legal risks.

For example, prospective employers could be accused of discriminating against an applicant based on seeing Facebook account information revealing someone's age or sexual preference.

"You shouldn't be forced to share your private information and communications just to get a job," Egan said.

"As the friend of a (Facebook) user, you shouldn't have to worry that your private information or communications will be revealed to someone you don't know and didn't intend to share with just because that user is looking for a job."

To enforce the point, Facebook made it a violation of its policy to share or solicit an account password.

"We don't think employers should be asking prospective employees to provide their passwords because we don't think it's right the thing to do," Egan said.

Facebook buys IBM patents
San Francisco (AFP) March 23, 2012 - Facebook confirmed Friday that it has added a trove of IBM patents to its arsenal on an increasingly lawsuit-strewn technology battlefield.

Reports that Facebook bought 750 software and networking patents from IBM surfaced less than two weeks after struggling Internet pioneer Yahoo! accused the thriving young firm of infringing on 10 of its patents.

"I can confirm that there was a purchase but I don't have any other details to share," Facebook spokesman Larry Yu said in response to an AFP inquiry.

IBM would not comment.

Acquisition of the patents came as California-based Facebook prepared for an initial public offering and as Internet titans increasingly battle in courts as well as in marketplaces.

Yahoo!, in a lawsuit filed in US District Court for the Northern District of California on March 12, accused Facebook of infringing on patents in several areas including advertising, privacy and messaging.

The Sunnyvale, California-based company asked the court to order Facebook to halt its alleged patent-infringing activities and to assess unspecified damages.

Facebook, which was founded in 2004, a decade after Yahoo!, expressed disappointment with the move.

"We're disappointed that Yahoo!, a longtime business partner of Facebook and a company that has substantially benefited from its association with Facebook, has decided to resort to litigation," a Facebook spokeswoman said.

In the suit, Yahoo! said that Facebook's growth to more than 850 million users "has been based in large part on Facebook's use of Yahoo!'s patented technology."

"For much of the technology upon which Facebook is based, Yahoo! got there first and was therefore granted patents by the United States Patent Office to protect those innovations," Yahoo! said.

"Yahoo!'s patents relate to cutting edge innovations in online products, including in messaging, news feed generation, social commenting, advertising display, preventing click fraud and privacy controls."

Once seen as the Internet's leading light, Yahoo! has struggled in recent years to build a strongly profitable, growing business out of its huge Web presence and global audience.