In 2006, the average price paid for a startup funded by venture capitalists rose 19 percent to $114 million. That was the highest amount since the dot-com frenzy of 2000 when the average price of venture-backed startups peaked at $337 million, according to data from Thomson Financial and the National Venture Capital Association.

If the dealmaking market continues to heat up, Zuckerberg will end up looking smart for rebuffing Yahoo and other suitors that included Microsoft Corp. and Viacom Inc.

Assuming Facebook hits its financial targets, the Palo Alto-based company should be able to command a sales price well above $1 billion or pursue an even more lucrative initial public offering of stock in the tradition of Google, Yahoo Inc., eBay Inc. and Amazon.com Inc. — a group of Internet icons now worth a combined $250 billion.

A Facebook sale or IPO is bound to happen eventually so the startup's early investors, consisting mostly of venture capitalists, can realize some profits. Facebook has raised about $38.5 million since Zuckerberg started the site in 2004 while he was still a sophomore at Harvard University.

Zuckerberg has some flexibility in deciding when to cash out because Facebook already is profitable.

An IPO or sale will "make sense at some point for the company, but I never think that's the goal," said Zuckerberg, who is believed to control nearly one-third of Facebook's stock. "The goal is to continue introducing certain revolutionary products that push us to the next level."

Marc Andreessen, who made a fortune during his 20s as co-founder of Web browser pioneer Netscape Communications, is among those who believe Facebook is going to become even more valuable during the next year or two.

"Facebook is doing the smart thing. If you are in a big market like social networking, you are usually better off waiting (to sell)," said Andreessen, who is now chief technology officer for another social-networking startup, Ning Inc. Had MySpace remained independent, it would probably be worth $5 billion now, Andreessen estimated.

Should Facebook stumble, it may some day be suffering the same pangs of regret tormenting Friendster Inc., which turned down a takeover bid from Google in 2003 when it reigned as Internet's hottest social-networking site.

Had that offer been accepted, Friendster founder Jonathan Abrams and a small group of early investors reportedly would have received $30 million in Google stock that would have been worth about $1 billion today.