LinkedIn’s IPO is priced at $45, which already gave it an incredible price-to-earnings ratio of 260. In the first day of trading, its shares more than doubled to $107 (at 11:53 a.m. ET), which takes the price-to-earnings ratio to more than 600.

LinkedIn does have a great story. It owns the social networking niche for US white collar professionals, a demographic that’s extremely attractive to advertisers. It’s able to charge human resource professionals for subscription accounts.

It has shown its ability to expand into job postings, a sector it could potentially dominate down the road.

Still, $107 a share – which values the entire company at over $10 billion even though 2010 earnings were just $15.4 million – seems expensive.

LinkedIn and its IPO have some similar characteristics with several Chinese internet tech companies and their IPOs.

These Chinese companies all have incredible stories and dominate important niches in the Chinese cyberspace. Moreover, they’re supported by the story of China’s growing middle class and consumer market.

On their first trading days on the NYSE, they soared. Youku (NYSE:YOKU) surged 161 percent, Qihoo 360 (NYSE: QIHU) jumped 134 percent, and Dangdang (NYSE:DANG) rallied 87 percent.

However, after their stellar first-day pop, their performance has been mixed.

Youku is now up 48 percent, Qihoo down 16 percent, and Dangdang down 32 percent.

LinkedIn, therefore, could suffer the fate of Qihoo and Dangdang.

Nevertheless, if its market share and business model remain intact, its stock should do well in the long-term.

Baidu (NASDAQ:BIDU), for example, surged 354 percent on its first day of US trading. Then, for the next few months, it steadily declined. Fast forward a few years, though, its shares have recovered and surged almost 1000 percent from the IPO price.

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