Facebook (NASDAQ:FB) launched its initial public offering today, becoming not only the third-largest IPO ever and the biggest tech IPO of all time, but absolutely dwarfing the rest of the previous deals in the social space. Though FB’s first day of trading was furious, with 567 million shares changing hands, the stock wound up pretty close to where it started, at $38.23. Still, Facebook is far and away the social media behemoth.

Here’s how its IPO compared to those of its sectormates:

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Since coming public in November, Groupon (NASDAQ:GRPN) has lost about half its value. But early this week, the company had a blow-out earnings report, which popped the stock. Unfortunately, the Financial Industry Regulatory Authority (FINRA) is now investigating the trading in the stock ahead of the earnings report.

The investigation is still in the early stages and may result in nothing. After all, Groupon’s stock was heavily shorted, and there may have been a “short squeeze.”

Then again, Groupon has already had issues, such as a restatement of its earnings. The company’s auditor also reported a “material weakness” in its internal controls. Read 

Facebook (NASDAQ:FB) pulled off its initial public offering, and it wasn’t without its drama — the deal suffered a 30-minute delay before finally launching. That might have been an omen that today wasn’t going to be as superlative as many had been betting.

FB shares opened up with about a 12% pop, hitting $42, which put a roughly $115 billion valuation on the company in the opening minutes. But after that, the price fluctuated throughout the day within a narrow range.

After sliding back to around the offering price at midday it was up again in afternoon trading to about $40, or 5% higher. But as the regular-hours trading day ended, Facebook has dropped again near to its opening price, closing up at $38.23 cents, or 0.6% higher. All in all, some 567 million shares changed hands today, and the stock went virtually nowhere. Read 

They’re annoying. They get in your way. They are pulsing blots on the mobile application landscape as cruel and unwanted as wasps at a picnic.

Of course, I am talking about ads in your favorite mobile applications. No, I don’t want to buy a Kia today, or tomorrow, or ever. Or Anacin. Or a Bud Light. Please, just go away.

But wait. It turns out there is a good reason for those ads to appear. Maybe I don’t mind putting up with them after all. Because it turns out that, increasingly, game makers and content providers are turning away from the 99-cents-per-app or $1.99-per-month subscription models and relying on ads instead to make their fortunes. Read 

At the close of the trading today, Facebook (NASDAQ:FB) priced its initial public offering at $38 a share, giving it a market value of $104 billion.

In all, the company is expected to raise $16 billion — good for the spot as the third-largest IPO in U.S. history behind Visa (NYSE:V, $19.7 billion in March 2008) and General Motors (NYSE:GM, $18.1 billion, November 2010). However, if extra shares reserved are sold too, Facebook could eclipse GM and raise $18.4 billion.

In light of all the hype, investors should be cautious tomorrow. As seen with other hot social deals — like Groupon (NASDAQ:GRPN), LinkedIn (NYSE:LNKD) and Zynga (NASDAQ:ZNGA) — investors would have gotten better valuations by waiting three to six months after the IPOs. Read 

“How can I buy Facebook stock?” my former colleague’s sister-in-law asked him.

“Do you have a brokerage account?” he replied.

“No.” Read