Canberra, Australia ? The repo man wants to “poke” you on Facebook. The bill collector is writing on your wall. What are you doing right now?

After a court in Australia ruled a mortgage lender can use Facebook to break the news to a couple that they have lost their home, the global social networking Web sites are threatened with turning a little more anti-social.

Some are concerned such court-approved contact with their social networks could amount to a violation of privacy.

“I don’t think people sign up to Facebook thinking it’s going to be another avenue by which a government agency or indeed a debt collector can contact them,” said Colin Jacobs, vice chairman of the technology advocacy group Electronic Frontiers Australia.

Facebook has become a wildly popular online hangout, attracting more than 140 million users worldwide since it began in 2004. Users can “poke” their friends — an electronic tap on the shoulder. They also can affix messages or attachments on a friend’s “wall” — an area on the Facebook page.

U.S. users don’t have to worry about being served through the program yet. Legal rules list several acceptable delivery methods, but not surprisingly, Facebook isn’t included, said Rory Ryan, a Baylor Law School associate professor who maintains a blog on such issues.