Facebook issued another acknowledgement regarding data privacy after it was revealed that certain applications on the social networking site improperly shared user data.

The company admitted that some of its popular applications sucy as FarmVille were to blame for sharing user information, as well as information about users' friends, with advertising and other Web companies. Facebook, which has been plagued by privacy concerns, promised to find ways to prevent a repeat incident in the future. They also stated that they were in discussions with developers of the applications regarding data privacy.

The Wall Street Journal initially broke the story that several applications were transferring User IDs, important pieces of identifying data, to outside organizations, which violates the privacy policy that Facebook established with its users. The user ID allows viewing access to the user's name and data that the user has specified should be public, but does not allow access to data that the user has set to be visible only to selected people on the site.

In its response to the leak, Facebook tried to allay fears about privacy and downplayed the importance of the user ID, saying that their release seemed to have been accidental. Mike Vernal, an engineer for Facebook, said on a company blog that "Press reports have exaggerated the implications of sharing" a user ID. Vernal states that "Knowledge of a UID does not enable anyone to access private user information without explicit user consent."

Privacy and technology experts had differing opinions of the potential impact of the leak.

In an interview with the New York Times, Peter Eckersly, a senior staff technologist for the Electronic Frontier Foundation, which deals with online freedom, said in response to the leak, "This is extremely serious." Though he acknowledged that there was no evidence of misuse of the data so far, he claimed that advertisers could create a link between the user ID and individual information available on the Web.

Other tech bloggers stated that the user ID is an insignificant piece of information and that other companies, such as credit card companies and magazines, possess many more details about consumers.

In a statement, Facebook announced plans to introduce "new technical systems that will dramatically limit the sharing of user IDs" and shut down applications violating the privacy policies if necessary.

The firm that created Farmville, Zynga, did not respond to press requests for comment on the issue.