LinkedIn Corp is banking on faster-than-expected revenue growth in 2011, as the professional networking site sets off to prove it can fulfill the promise of its splashy IPO and rich valuation.

LinkedIn -- used by professionals seeking jobs or contacts and companies searching for qualified applicants to fill slots -- was the first prominent U.S. social networking site to make its public debut. Shares of the company more than doubled its initial public offering price on its first day of trading on the New York Stock Exchange in May, whetting the appetite of investors for a Facebook IPO.

The company's first full results report since its May debut will be picked apart by investors for clues as to whether the stock's lofty valuation -- estimated at more than 30 times sales -- is justified.

The Mountain View, California company had warned it will not be profitable in 2011 as it shovels funds into expansion -- hiring field sales representatives and launching new products. But investors have brushed off those concerns for now.

Shares of the company are still trading at well above their $45 IPO price, despite persistent worries of a dotcom bubble reminiscent of the late 1990s.

"We see great things for it. Some of what is happening in the marketplace is, investor demand for social media companies is taking precedence over the cash value of the underlying shares," said Evercore Partners analyst Ken Sena.

"They did set the bar really low. The numbers needed to be good to support the lofty valuation."

LinkedIn must now continue to fuel its growth both by encouraging its members to consistently use the site and seek out new international audiences while the broader U.S. job market struggles to get out of a deep and persistent slump.

It forecast third quarter revenue of $121 million to $125 million, ahead of analysts' average projections for $111.8 million. And the company foresees revenue of $475 million to $485 million in 2011, again ahead of estimates of $467.7 million.

FROM LIVING ROOM TO NYSE

LinkedIn is one of clutch of closely watched Internet social media companies -- including Groupon, Zynga, Twitter and Facebook -- that have stoked investor interest.

The company -- started in the living room of ex-PayPal executive Reid Hoffman who co-founded the company in 2002 -- makes money by selling premium subscriptions to its members and by helping companies with hiring and marketing.

Its membership base -- a closely watched metric as the underpinnings of its hiring and advertising business model -- climbed to 115.8 million, up 61 percent from the second quarter of 2010.

LinkedIn said second-quarter revenue leapt 120 percent to $121.0 million, surpassing an average forecast of $104.73 million according to Thomson Reuters I/B/E/S.

Second-quarter net profit rose slightly to $4.5 million from $4.3 million a year earlier. Excluding certain items, it earned 4 cents a share, outstripping forecasts for a loss of 3 cents a share.

In particular, revenue from hiring solutions, or services that help companies hire employees -- which makes up the bulk of the social network's business -- surged 170 percent to $58.6 million, racing past expectations.

Revenue from marketing solutions jumped 111 percent to $38.6 million, while sales of premium subscriptions rose a more sedate 60 percent to $23.9 million.

Shares in the company gained about 3 percent to $98.50 in after-hours trade, after shedding more than 9 percent of their value in regular NYSE trading.