Google co-founder Sergey Brin said social networking site Facebook, which has been rumored to be in talks with the search giant, is not for sale.

"If they come to us, we'd certainly be open to talking," Brin said, answering a reporter's question at the 25th annual Allen & Co. media deal-makers conference in Sun Valley, Idaho. "But I think they're building a great company of their own."

Facebook's founder Mark Zuckerberg has insisted that he intends to build an independent company, despite rumors that Google, among other internet titans, have been courting the social network.