Shares of LinkedIn (LNKD) jumped sharply in after-hours trading after the social networking site reported an unexpected profit of 10 cents a share on revenue of $121 million.

Analysts had predicted a loss of 3 cents on revenue of $105 million.

Revenue more than doubled from a year ago, when $54.9 million was reported.

The stock regained all of its earlier losses in after hours trading, rising $9.46, or nearly 10%, to $105. During the regular session the shares fell $10.13, plunging along with the broader stock market on a range of economic concerns.

This is LinkedIns first earnings report as a publicly traded company. LinkedIn was the first of a new wave of high-profile Internet companies to sell its shares to the public. Groupon, Zynga and Facebook are expected to follow, and all are expected to duplicate LinkedIns spectacular gains.

The companys wildly successful IPO in May was controversial in that the shares were priced initially at $45 and they immediately doubled after hitting the stock market. The sharp increase led to criticism that underwriters had mispriced the deal by underestimating demand.

Also, some analysts said investors were overvaluing the company, much like investors did a decade ago when Internet companies first began going public.

But LinkedIn sold a very small number of shares, just an 8% stake, or 7.8 million shares, which helped drive up demand.

LinkedIn allows professionals to network by sharing resumes and other contact information.

Follow Dunstan Prial on Twitter @DunstanPrial