Talk about a first-day IPO pop.

LinkedIn shares, priced at $45 for the IPO, surged to almost $93 in the morning session of its first trading day, before settling down at $85 per share at 10:43 a.m. Eastern Time.

Based on 2010 earnings, its price-to-earnings ratio just topped 500 and the company’s valuation exceeded $8 billion.

LinkedIn is the hottest US tech IPO since 2004 – until the day Facebook eclipses it with an even bigger IPO of its own.

LinkedIn boasts of 37-million monthly US visitors (which makes it the 26th most visited website in the US) and 100 million registered users.

It’s already a profitable company. In 2010, its revenues were twice the 2009 figure. If revenues double again in 2011 (and in 2012) and earnings will also improve, the high valuation would look more justified.

LinkedIn's incredible first-day IPO pop, however, actually pales in comparison to Chinese tech companies.

Youku (NYSE:YOKU), dubbed the “Chinese Youtube,” surged 161 percent in its first day.

Dangdang (NYSE:DANG), the “Chinese Amazon,” surged 87 percent on its first day and Qihoo 360 (NYSE:QIHU) jumped 134 percent on its first day.

Investors were more bullish on the Chinese tech companies because they arguably have some of the same advantages of LinkedIn but also tap into the vast potential of the Chinese consumer market.

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