LinkedIn Corp. (Nasdaq: LNNKD), the biggest professional-networking website, forecast sales for the third quarter and full year that topped analysts’ predictions as it adds users and makes more money from recruitment services.

Revenue this quarter will be $235 million to $240 million, Mountain View, California-based LinkedIn said in a statement Thursday.

Full-year sales will be $915 million to $925 million, ahead of the $880 million to $900 million it projected in May.

Analysts on average were predicting third-quarter sales of $236.3 million and 2012 revenue of $906.3 million, according to data compiled by Bloomberg.

Chief Executive Officer Jeff Weiner has lured subscribers and increased revenue from hiring services, the largest of the company’s three main product lines. The first among social media companies to hold initial share sales since early 2011, LinkedIn has done a better job than consumer-focused peers Facebook Inc. and Zynga Inc. at wringing sales from a growing user base. It’s also more adept at managing expectations, said Tom Forte, an analyst at Telsey Advisory Group in New York.

“Their execution since becoming public has been the best of the newly minted Internet companies,” said Forte. “This has been a consistent beat-and-raise story.”

LinkedIn’s shares rose 7.3 percent to $100.35 in extended trading Thursday after falling 2.2 percent to $93.51 at the close in New York. The stock has risen 48 percent so far this year.

Falling Profit

Sales in the second quarter also topped predictions, increasing 89 percent to $228.2 million, compared with the $216.5 million average analyst estimate compiled by Bloomberg.

Profit declined as Weiner increased spending aimed at recruiting more business from employers seeking to hire. Net income fell to $2.81 million, or 3 cents a share, from $4.51 million, or 4 cents, a year earlier. Profit excluding some items was 16 cents, matching estimates. Costs soared 93 percent to $214.7 million, with sales and marketing more than doubling to $75.7 million.

LinkedIn grew its base to 175 million members, up from 161 million in the first quarter, as more people accessed the site from mobile devices such as Apple Inc.’s iPad, the company said.

Some social media companies, including Facebook, have had a harder time making money from mobile users than from those who socialize on larger screens.

‘Beyond Advertising’

LinkedIn is developing services for smartphones and tablets that would appeal to paying subscribers, Weiner said on a call with analysts yesterday. He declined to elaborate.

“It’s important to recognize that when we talk about mobile monetization, it goes beyond advertising,” he said.

Almost a quarter, or 23 percent, of visits to LinkedIn happened on mobile apps last quarter, up from 10 percent a year earlier, Weiner said. More than 15 percent of new member sign- ups were from mobile, he said.

LinkedIn revamped its home page last month to highlight the activities of a member’s professional connections, including articles read and changes to work profiles. The changes have resulted in record levels of activity, LinkedIn saidThursday.

Facebook and Zynga have both declined after reporting second-quarter results that disappointed investors. Facebook, down 47 percent since its May IPO, is struggling to accelerate sales growth, while Zynga, down 73 percent since its December share sale saw a drop in demand for virtual goods.