Friendster, which predates Facebook and MySpace in the social networking space was founded in 2002. But it quickly lost ground to other social networking sites in the United States. Friendster is now mostly used in Asia where more than half of its registered 100 million users are from.

Friendster will be sold to an Asian listed firm for more than $100 million in a deal set to be announced by the end of the month, said a source who declined to be identified as the information was not yet public.

TechCrunch, an industry blog, said in July it valued Friendster at $210 million, a fraction of Facebook's estimated $10 billion valuation.

Friendster chief executive Richard Kimber told Reuters that Morgan Stanley had been hired to handle the deal.

"We have a shortlist at this point that we are negotiating with," Kimber said.

Friendster, like Facebook, has been struggling to find an effective monetisation strategy. The firm rebranded its main website on Friday targetting a younger audience and said it will shift its revenue focus from advertising to micro-transaction.

Headquartered in California, Friendster had turned down a $30 million buyout offer from Google Inc six years ago, according to newspaper reports.

Tencent Holdings, China's largest Internet firm by market value at $35 billion, was among the short-listed bidders, while Facebook also showed interest but was turned down due to competition and intellectual property issues, the source said.

Friendster holds five U.S. patents related to social networking according to the United States Patents and Trademarks Office.