Given the media blitz on Facebook's plans for an IPO, by now it seems we've learned everything about the company except what CEO Mark Zuckerberg eats for breakfast.

Maybe one of the TV tabloid shows will fill us in on that soon.

Meanwhile, what I really want to know are the answers to the following key questions: Will the company be overvalued? Does Facebook have a future, or will the IPO mark its top? How much will shares cost me? What are the real risks?

And based on all that, should I buy the darn stock?

I recently talked with a half dozen or so tech and media experts, including a few who already own the stock via the private market, and I came away with the following key takeaways. Call it a field guide to the Facebook IPO.

Takeaway No. 1: Shares will be 'overvalued,' but so what?

According to numbers leaked to the media by Facebook IPO insiders, the social-media site will come public with a market cap of $75 billion to $100 billion. Given the trailing annual revenue of $3.7 billion and trailing earnings of $1 billion, the company will have a price-to-earnings ratio of 75 to 100, and a price-to-sales ratio of 20 to 27.

Those seem like crazy numbers, compared with price-to-earnings and price-to-sales ratios of 20 and 5 for Google (GOOG, news)and 13 and 3.3 for Apple (AAPL, news). But they really aren't too high if you, like many investment pros, believe this is a game-changing company in the early stages of its growth.

"It doesn't sound too ridiculous," says Michael Scanlon, a tech analyst with the John Hancock Balanced A (SVBAX) fund. He points out that Google carried what seemed like a crazy price-to-sales ratio of 23 when it came public, and the stock has done incredibly well since.

image: Michael Brush

Michael Brush

"Facebook is still in its infancy. Social-media spending is a fairly new initiative for Fortune 500 companies, so it will take a while for them to figure it out," he says. Advertisers had the same attitude toward the Internet a decade ago. But online ad spending is set to surpass offline ad spending for the first time this year.

"This kind of offering is a battle between people who argue it is insanely expensive and people who look at the huge footprint the company has and how they have only scratched the surface of monetizing that," agrees Kevin Landis, portfolio manager of Firsthand Technology Value (SVVC) fund, which has more than 5% of its assets in Facebook, the fund's largest position. "It is almost not worth arguing what the right multiple is. If they fully take advantage of their possibilities, they could be worth more than Google."

Hmmm. Valuation doesn't matter? Didn't we hear that during the tech bubble about a lot of companies that didn't survive?

Yes. But some of the companies from that era were game-changers worth paying a little extra for -- think Amazon.com (AMZN, news) and Google. Which brings me to the next key takeaway:

Takeaway No. 2: Facebook is a real game-changer

In the run-up to Facebook, a string of social-networking stocks went public last year. And investors who bought their IPOs have generally lost money. (Read "The year of the broken IPO.") So why pay a bundle for this one?

Because Facebook is "just another social-networking stock" the way Google was "just another search engine." It's the company that defines how to make money in the sector.

"Facebook, to me, looks dominant," says veteran investor Tom Vandeventer, portfolio manager of the Tocqueville Opportunity (TOPPX)fund, which has about 2% of its portfolio in Facebook. "This company has one of the most compelling business models that I've seen in 30 years. It has the ability to really take a lot of market share in advertising."

As evidence, Vandeventer cites some of the stats that Facebook released in its IPO filings. A key one: Facebook numbers on what it calls "engagement." Users post 2.7 billion "likes" and comments a day, or five or six comments per user, per day, for the most-active user base of about 500 million. (Total membership is 845 million.)

"It is not a pass-through site. That makes Facebook very competitive. That is what people underestimate here," says Vandeventer. This helps give Facebook the all-important defensive moat that investors look for. "I don't see the entrenched Facebook user base going anywhere. They're not going to leave their friends and friend circles."

While you're on Facebook, of course, it is gathering tons of intensely personal information about you, which it can then use to target ads -- something that no other site can do as well. "When Google tries to take advantage of this, it feels kind of creepy," says Landis. "When Facebook does it, it's much harder to complain because you gave it up. You posted all that stuff."