Facebook is unlikely to go public for at least 18 months, and would consider a buy-out offer only of $10 billion or more, one of the company's directors has said.

Director Peter Thiel said that speculation that the fast-growing networking site was on the verge of listing was misplaced and that the earliest Facebook would file for an IPO would be 2009 — "and hopefully not until significantly after that."

He said the company was under no pressure to raise funds.

Analysts and others had "read too much" into a recent job listing on Facebook's website for a stock administration manager to manage its options programme — a position which usually only a public company would require, Mr Thiel told The Deal in an interview.

Facebook - which has 52 million users worldwide, and is growing its subscriber base at a rate of 89 per cent a year, has been the subject of widespread speculation in recent months.

Last year the firm, which is run by Mark Zuckerberg, its 23-year-old chief executive, reportedly turned down an offer of $1 billion from Yahoo!.

Asked whether Facebook would list or consider a buy out, Mr Thiel said: "I think the preference we have would be to do neither," adding that it would take a significant sum to gain the management's attention.

"If we got an offer from someone of $10 billion, we would probably listen to them. I don't think we're going to get that offer, and we're not going to solicit," he said.

Mr Thiel, one of the company's early backers who invested $500,000 for an undisclosed stake in 2004, said that Facebook was on track to earn $150 million in 2007 - the vast majority of which will come from advertising.

The reason a sale was unlikely was because of the "significant valuation gap" that existed between potential buyers and Facebook's board, he told The Deal.

Tomorrow Mr Zuckerberg will face court in Boston, Massachusetts, accused of stealing the idea — and source code — for Facebook from ConnectU, a similar, university-based social network site, for which he worked as a programmer four years ago.

ConnectU's founders have asked that Facebook be shut down and that control of the site — and its profits — be handed over to them, in an action which accuses Mr Zuckerberg of copyright infringement, misappropriation of trade secrets, and breach of contract.

Mr Zuckerberg denies any wrongdoing and his lawyers have asked that the judge dismiss the case.

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