Linkedin Inc. was listed on the New York Stock Exchange on Thursday. (MIKE SEGAR/REUTERS)

The frenzy around LinkedIn has many people asking: Are we reliving the tech bubble of the ’90s?

Over the past 12 months, LinkedIn has made about 7 cents per share. This morning, investors are paying a thousand times that value and betting that the company’s earnings will rise higher than its $9 billion valuation.

Is this indicative of a bubble? According to The Economist, the answer is yes. And no.

Based on secondary-market trades, Facebook and Twitter have been estimated to be valued at $76 billion and $7.7 billion, which is more than Boeing or Ford, according to The Economist. That’s where the bubble is, the magazine pointed out in its cover story this week. It it were to pop in those private markets -- including Facebook, Groupon and Twitter -- it would have a limited effect on overall stocks.

Also, the companies getting the most buzz are proven sites. The New Yorker’s John Cassidy, who wrote a book on the first dot-com bubble, noted that Facebook is far more secure than public companies such as or Webvan. But once these more proven companies do go public, there could be trouble as potential copycats look to ride their coattails. The bubble, The International Business Times said, will grow when any social-media or tech startup becomes a hot-ticket item just for being in the industry.

A tech bubble could bring more global repercussions than did the bust of 2000, according to the Economist. Tech startups are cropping up around the world. If a new bubble pops, it could reach far beyond Silicon Valley.

LinkedIn made $94 million in the first quarter of 2011, and its net income was $15.4 million in 2010, the Wall Street Journal reported. Thursday’s IPO made LinkedIn chief executive Reid Hoffman a billionaire. His personal stake is now valued at $1.6 billion.

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