Whereas Netscape's IPO symbolized the dawn of the dotcom boom, TheGlobe.com's epitomized the height of irrational exuberance and Google's ushered in a renaissance of tech innovation after the Internet bubble burst, LinkedIn's debut will be remembered as social media's arrival on the capitalist stage known as Wall Street.  For starters, LinkedIn's lofty valuation by most anyone's standards (at Thursday's closing price of $94, it's trading at 36 times its 2010 revenue; Google trades at five times) will have venture capitalists scrambling to take their Internet investments public.  As venture capitalist Albert Wenger put it on Twitter, "LinkedIn is Netscape of this decade. IPO window blown wide open."  Further, the social dynamics that companies like LinkedIn thrive on offer something completely different from the first-generation Internet companies: incredibly rapid and organic growth. Whereas in the 1990s, Web companies shelled out tens of millions of dollars on advertising to find users, today's social media leaders like LinkedIn acquire new users through network effects -- their services become more valuable to users when their friends sign up.  This trend isn't going away, and there are undoubtedly dozens if not hundreds of little-known or yet-to-be-founded startups that will go from zero to publicly traded juggernaut in remarkably shorts periods of time.  Add to that the fact that Internet companies with a lot more sex appeal than LinkedIn -- including Facebook, Groupon, Pandora, Yelp and Zynga (makers of FarmVille) -- are all likely to go public within the next year, and you have LinkedIn taking the pole position in what will be a tidal wave of social media companies entering the public markets.
When the dust settled on LinkedIn's IPO on Thursday afternoon, the company was valued at $8.9 billion, making it worth more than household names like JC Penney, Electronic Arts and Chipotle.As the