Google Inc.'s online communities have little traction in the United States, but the Web search leader continues to seek a spot in the social-networking hierarchy.
First, it must contend with Facebook Inc., the No. 2 online hangout behind MySpace Inc.
Days after Google unveiled Friend Connect, which lets the sites of musicians, political campaigns and others incorporate profile data from several social networks, Facebook began to block the program.
Although Google was taking advantage of the same tools Facebook made available for free to other outside developers, Facebook said Google was violating Facebook's restrictions on sharing data.
Google, whose Orkut social network has tens of millions of users in Brazil, tried to reach further into social networking with the November unveiling of a consortium called OpenSocial, which lets developers write programs for use on multiple social networks. News Corp.'s MySpace has joined, but Facebook has not.
This month, Google unveiled Friend Connect, which promises to pool profile data from Facebook, Google Talk, Orkut, LinkedIn, Plaxo and hi5, though not MySpace. The profile information is incorporated into other sites -- a political campaign, for instance, can build communities of supporters by tapping existing networks -- with Google serving as the intermediary.
Facebook quickly objected, citing privacy concerns. It normally deals with other companies one on one and can block a service that it believes violates its rules. With Google as the go-between, Facebook lost that leverage, so it decided to block Friend Connect entirely.
In a blog posting, Facebook developer Charlie Cheever said Google's 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."
Google acknowledged that it passed along data. But it said the sharing was limited to links for profile photos of users and friends who had expressly consented to sharing with that particular site.
Facebook has run into privacy challenges before, most recently when it unveiled a marketing tool called Beacon that tracked purchases Facebook members made on other websites and sent alerts to their Facebook friends about the transactions.
But Rachel Happe of research firm IDC said the dispute was about control rather than privacy. She said Google's Friend Connect "starts to eat into other people's value proposition, which is why you saw Facebook object to it."