Well, just ask Mark Zuckerberg!

This afternoon, at an all-hands meeting held in a Palo Alto, Calif., theater near the social-networking site’s headquarters, the 23-year-old founder was quite voluble on that topic, outlining numbers that a more experienced CEO might think twice about unveiling to a large audience.

With an open dial-in number! Many employees, in fact, were horrified that Zuckerberg would be so blabby about such important financial information. Others loved it.

Most were simply surprised (although, to be fair, Google Co-Founders Larry Page and Sergey Brin used to give a lot of detailed company info to their employees before going public, but in coordination with other execs).

“I can’t believe he was doing it,” said one. “It was really unbelievable.”

Believe it! Some highlights?

Revenue for Facebook for 2007 will be $150 million, as has been widely reported. But for 2008, Zuckerberg projected revenue to be increased to $300 million to $350 million.

More interesting was the news that Facebook would spend $200 million next year on capital expenditures, which is a whole lot of servers.

By the way, more expenses, noted chatty Mark, those employee levels would rise to more than 1,000 in 2008 from 450 now.

And Zuckerberg also said the company’s EBITDA–earnings before interest, taxes, depreciation and amortization and a number widely used by Wall Street as an indication of operating performance–would be $50 million in 2008.

That means the company would have a negative cash flow of about $150 million (EBITDA minus CapEx), rather than break even, as it does now.

But who’s counting? Zuckerberg apparently said he did not care about maintaining EBITDA anyway.

That’s because Facebook collected $300 million in investments recently from Microsoft and other investors, which pegged the valuation of the company at $15 billion.