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With Facebook shares Tuesday morning trading $7.80 below their offering price, mom-and-pop investors alone are out more than $800 million. And that's the good news. Now here's the bad: Whatever the right number is for how much we've lost so far -- get ready to double it.

Not much, and the jokes on you if you think otherwise. As the Facebook IPO makes abundantly clear, ordinary investors need to stop counting on Wall Street to look out for them.

Facebook has ended its third trading day and the world is falling apart -- again. The stock closed Tuesday at $31, down 19% from the $38 IPO price, lead underwriter Morgan Stanley is under fire, the SEC is ready to investigate, and analysts are blaming everyone. Oh, and the fundamentals? Those haven't changed a bit.

Forget how Facebook is beating up its IPO investors: The social network is still giving many other publicly traded companies fits. And these five in particular are seeing their business models take a hit at Facebook's expense.

On Saturday, Mark Zuckerberg tied the knot with his college sweetheart, Priscilla Chan. Here's a gallery of their time together, as told through their Facebook timelines.

On Monday, Facebook's stock fell from its IPO price of $38 to a low of (as of this writing) $33.60. So what? Nobody who actually paid attention to Facebook's statements before the IPO should be surprised by this latest turn, or even worried. Here's why:

Stock futures are rising with a new survey suggesting that economists are a bit more optimistic about housing and employment. The National Association for Business Economists' forecasters expect modest growth for the rest of 2012, with the pace picking up in 2013.

The Facebook IPO is making dozens of people phenomenally rich. How rich? Check out CNBC's list of top shareholders, see and the amounts of their Facebook windfalls as they move based on the real-time price of the shares.

For your reading pleasure while you watch the roller coaster ride of Facebook's Friday trading debut, here's a list of facts about the company and CEO Mark Zuckerberg that aren't widely known.

Facebook finally set its IPO price Thursday evening: $38 a share, for a record-setting value of $104 billion on the social media giant. Is it worth it? Who knows. But despite the skeptics, there are definitely ways to make money from all those Facebook users' eyeballs.