The patent wars raging between tech firms dominating the mobile device market could spill over in the equally lucrative social networking sphere as Yahoo reportedly sent notice to Facebook this week demanding for licence payments.

New York Times first reported on Monday a meet that took place between representatives of the two tech titans, one struggling to reassert its hegemony in the lucrative search engine market now ruled by Google and the other considered by the tech world as its rising star.

That stature alone has attracted numerous lawsuits for Facebook or its founder Mark Zuckerberg, mostly claiming that the young CEO had put together his hugely popular social media firm using ideas culled from others.

Reuters has reported that talks were underway between Yahoo and Facebook, indicating that a lawsuit is not yet imminent and could be prevented if an amicable settlement would be agreed upon, the exact amount of which remains a mystery.

Yet the Associated Press (AP) quoted one Yahoo shareholder as saying that the company could be seeking billions of dollars from Facebook, basing the assumption on the 2004 Yahoo-Google deal that settled the two firms' patent claims on online advertising.

Yahoo collected a windfall amounting to $230 million on that tiff, AP said.

And Eric Jackson of Ironfire Capital was optimistic that Yahoo's licensing claims would lead to billions.

"As a shareholder, I am happy they are going after Facebook. It's a perfectly legitimate thing for them to do," Jackson told AP.

Yahoo's claims largely rest on how Facebook renders the technical functions of the social media site's advertising services, news feeds, messaging services and privacy control, Reuters said citing its unidentified source.

In a statement it sent out Tuesday, Yahoo said "we must insist that Facebook either enter into a licensing agreement or we will be compelled to move forward unilaterally to protect our rights."

"Yahoo has a responsibility to its shareholders, employees and other stakeholders to protect its intellectual property," the search engine firm added, which in the previous years has been struggling to reformulate its business to hopefully regain its old glory.

The company also stressed that patents claims lodged by Yahoo before other firms have been acknowledged and honoured, with license agreements already sealed.

A similar set-up should not be a problem with Facebook in light of the airtight precedents that have been established before, Yahoo said.

Reacting to media queries, Facebook said that Yahoo's claims were now under study but the company declined to provide further details.

"Yahoo contacted us at the same time they called the New York Times and so we haven't had the opportunity to fully evaluate their claims," the social media giant said in a statement.

Experts have been harping on the likelihood that Facebook, along with other social networking sites, would face an avalanche of patent claims following its earlier initiative of going public.

Facebook's initial public offering (IPO), once formally completed, could bring up the company's market value by $100 billion, possibly nudging the internet firm in almost equal standing with Apple, currenlty the world's most valuable tech firm.