CNN's top story Monday read: Facebook Now Worth $50 Billion. Next to the headline was a portrait of Facebook CEO Mark Zuckerberg.

"I wonder what it's like to be Zuckerberg," I asked one of my Foolish colleagues. "Wake up in the morning. Check the day's top news stories. First item on the list: Me. I'm loaded."

Then it hit me. Is this really a big deal? A company has a $50 billion market cap and it's breaking news?

Forty-nine S&P 500 companies have a market cap north of $50 billion. Do we drool over them? No. CNN will never run a top story that says Breaking News: Occidental Petroleum Now Worth $79 billion. But it is.

So why are we so obsessed with Facebook's valuation?

One, it's a young company started by college dropouts. Zuckerberg -- Time's person of the year -- is 26, looks 16, and judging by his public appearances has the social skills of a soccer ball (ironic, given his line of work). With a $50 billion valuation and estimates that he owns a quarter of the company, Zuckerberg is worth about $12.5 billion. Facebook started seven years ago. Do the math: He's earned about $3,400 per minute of Facebook's existence. Newsworthy? Oh yes. I'm fascinated.

But maybe there's another reason we're so crazed about Facebook's valuation.

It's lunacy.

If we're talking online media companies, Google (Nasdaq: GOOG) was also worth $50 billion in 2005. The difference? In 2005, Google had net income of $1.5 billion. Most sources say Facebook has revenue of about $1.5 billion. In other words, investors are valuing Facebook at a price-to-sales ratio similar to the price-to-earnings ratio of a young Google. I'm obviously not the first to shake my head at this. "I'm no Benjamin Graham, but even I can see that shares of Facebook today are trading for, ohhh, about 50 times sales and at least 1,000 times earnings," wrote my colleague Nick Kapur last week.

And face it. What little we know about this company's finances doesn't make one terribly enthusiastic. Facebook's home page contains 20 words, six of which are, "It's free, and always will be." Assuming it's somewhat accurate, the movie The Social Network portrays Zuckerberg as being mostly against monetizing the site at all. He wanted a great company, which he obviously distinguished from a profitable company.

Back in the real world, Zuckerberg remarked in 2004 that "we're definitely not in it for the money." Granted, that seems to be the key behind Facebook's popularity: It focuses relentlessly on the quality of its product, end of story. That's admirable, and keeps users coming back day after day. But product success and financial success are two very different things. Investing in a company whose CEO seems indifferent to financial success doesn't strike me as appealing.

I think it boils down to this. Those investing in Facebook aren't doing so because they think shares are cheap. They're doing it either for ancillary benefits -- Microsoft's (Nasdaq: MSFT) 2007 investment that provided exclusive advertising privileges, or Goldman Sachs' (NYSE: GS) recent backing that could give the bank first dibs for underwriting a Facebook IPO -- or for the greater fool theory that public investors will become so captivated by Facebook's large numbers (750 million pictures uploaded over New Year's weekend!) that we'll look past its relative financial shortcomings once it IPOs.

Maybe I'm wrong. There's no public information on Facebook's financials after all. Those who have invested in the company at a $50 billion valuation know much more than I do. But we've seen this play before. Become obsessed with an inspiring and popular company, forget about finances, and bid valuations to the moon. It never ends well.

Fool contributor Morgan Housel owns shares of Microsoft, and has been a happy Facebook member since 2005. Google and Microsoft are Motley Fool Inside Value selections. Google is a Motley Fool Rule Breakers pick. Motley Fool Options has recommended a diagonal call position on Microsoft. The Fool owns shares of Google, and Microsoft. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.