Google Inc.’s online communities have little traction in the United States, but the search leader continues to seek a spot in the social-networking hierarchy.

First, it must contend with Facebook, the No. 2 online hangout behind MySpace.

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 that Facebook made available free to other outside developers, Facebook said Google was violating Facebook’s restrictions on data sharing. The two sides remain in a stalemate.

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 applications for use on multiple social networks. News Corp.’s MySpace has joined, but Facebook hasn’t.

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 gets 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. Normally dealing with other companies one on one, Facebook can block a service it feels violates its rules. With Google as the intermediary, 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 responded, acknowledging it passes along data. But it said sharing is limited to links for profile photos of users and friends who have expressly consented to sharing with that particular site. The user’s name and numeric ID on Facebook are replaced with Google’s own identifiers, Google said in a company blog post.

Google also said it purges Facebook data from its systems every 30 minutes, more frequently than the 24 hours required by Facebook.

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 Web sites and sent alerts to their Facebook friends about the transactions.

But Rachel Happe, research manager at IDC, said the dispute is ultimately 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.”