Facebook Inc. (NASDAQ: FB), LinkedIn Corporation (NASDAQ: LNKD), Zynga Inc. (NASDAQ: ZNGA), CrowdGather Inc. (OTCBB: CRWG) and other social media companies have a wide array of valuations in the public markets. In this article, we’ll compare those valuations to determine the most underpriced and overpriced plays in the burgeoning industry.

Take a look at some popular social media firms from a comparative view of P/E ratios, Price-to-Book, Revenue Growth and Market Caps.

In case you have not heard, Facebook (FB) goes public today and its initial public offering makes it the most valuable company at the time of its offering to ever go public. At $38 a share the company is valued at $104 billion.

While demand to own a stake in the tech giant has been much greater than any would have expected, a new AP-CNBC poll shows that 50 percent of Facebook users believe the social media network may be just a passing fad.

As Facebook (NASDAQ: FB) prepares to go public this Friday, it is already moving to show potential investors new monetization opportunities. Facebook Highlights is an initiative the Palo Alto, California-based social network is testing in selected geographies, whereby regular users pay so that their social updates get preferential treatment across all of their friends' news feeds.

Instagram, having only a dozen employees was sold for a billion dollars to Facebook. What makes Instagram, a photo sharing app so valuable to Facebook?