Facebook isn't feeling very social toward Google. The social networking site on Thursday broke up with Google Friend Connect -- the search company's system for adding social features to any Web site. It denied Friend Connect access to Facebook user data for failing to respect its privacy requirements.

"We've found that [Friend Connect] redistributes user information from Facebook to other developers without users' knowledge, which doesn't respect the privacy standards our users have come to expect and is a violation of our Terms of Service," said Facebook engineer Charlie Cheever in a blog post. "Just as we've been forced to do for other applications that redistribute data in a way users might not expect or understand, we've had to suspend Friend Connect's access to Facebook user information until it comes into compliance."

Joe Kraus, director of product management at Google, disputes Cheever's contention that privacy is the issue. "We really think that the broad issue here is 'do users have control of their data?'" he said. "And we think that Friend Connect gives users control of their data. Obviously we're disappointed that Facebook doesn't want to let its users access their friends on Friend Connect. We really think this is an issue of user control."

Privacy, Kraus said, isn't the problem. "Google stores no social graph data from any of the social networks," he insisted. "None. ... What Google stores is just a Friend Connect ID, which is just a number, and whatever security token that the social network gives us back. That's all. We don't store credentials, we don't store profile data."

Kraus added that at the recent developer event where Friend Connect was introduced, officials from business social networking site LinkedIn expressed approval of the way Friend Connect respected user privacy.

Facebook did not immediately respond to a request to explain what Facebook user information Google Friend Connect allegedly redistributes.

"Google lives and dies on protecting users' privacy," Kraus added. "We believes [Friend Connect] is good for users in terms of control and extremely protective of user' privacy."

Research firm IDC also sees control as the issue. "Facebook, MySpace, Yahoo, and Google are fighting to reign as this central account for Web users," analyst Caroline Dangson said in a research note published on Monday.

Dangson cast the fight as an effort by Google to de-emphasize the user-centric, site-centric vision of online interaction that has emerged around social networking sites in favor of a more dispersed, modular model that benefits from Google as its center of gravity.

"Google Friend Connect puts Google in the middle of the social graph by mediating the relationship between people's content (their blogs, etc.) and their friends -- a smart but also a bit devious as a competitive move," she wrote.

Kraus insists Friend Connect benefits social networks and their users. "It makes those relationships you establish on social networks more useful on more places," he said. "And if the user so chooses, it makes the activity streams, or updates streams -- whatever you want to call them -- richer within those social networks."