Holy cow, Facebook is worth $10 billion? That may be how the social networking Web site would like the world to interpret its latest capital infusion. But don’t be fooled. While that may represent a target valuation for Facebook, the actual worth, today, of Mark Zuckerberg’s dorm room creation may be much lower.

That’s not to completely dismiss the headline figure. Under terms announced Tuesday, the Russian Internet investment group Digital Sky Technologies is plugging $200 million into the company for about a 2 percent stake. By that arithmetic, Facebook would indeed be worth $10 billion.

For a company that, by its own admission, won’t generate positive cash flow until sometime next year, that’s an impressive figure to bandy about. True, Facebook’s last capital-raising 18 months ago, which brought Microsoft and the Hong Kong tycoon Li Ka-shing in as investors, put a $15 billion price tag on the company. But considering the trajectory of financial markets since then, the valuation attached to Digital Sky’s trade actually looks even more robust.

Shares in the technology bellwethers Microsoft and Google have plunged about 45 percent since November 2007. Assume a similar decline in Facebook’s value and, on a market-adjusted basis, Digital Sky is arguably paying at least a 20 percent premium to Microsoft’s entry price, ignoring growth in Facebook’s business in the meantime.