The Facebook IPO was this week’s biggest story. The social media giant, which boasts 800 million members, is seeking a $75-$100 billion market valuation. But hold your horses, investors. A lot of that optimism could be empty hype. After all, look at the site’s requested valuation as a percentage of its 2011 revenue, and compare it to other tech giants like Google and Microsoft. Also, contrary to Mark Zuckerberg’s claim, most of the world does not, in fact, “have access to the internet or mobile phones.”