Shares of Facebook (Nasdaq: FB), the No. 1 social networking site, soared as much as 24 percent after the company reported third-quarter results that exceeded estimates.

Facebook shares closed at $23.21, up $3.71 or 19 percent, after trading as high as high as $24.25 in the morning. and kept trading around that level. They were priced at $38 in their initial public offering on May 17 and closed at $38.23 on May 18, the first day of public trading, so they're still down 39 percent.

Citi Research analyst Mark Maheny was among several Facebook analysts to upgrade his recommendation on Facebook shares to “buy” from “hold” after listening to CEO Mark Zuckerberg Tuesday night explain growth for the company.

So did Jordan Rohan, analyst with Stifel Nicolaus, who was especially pleased that Facebook's revenue from mobile platforms jumped to $153 million in the third quarter, or about a quarter of overall revenue.

"We're only just getting started on mobile," said Zuckerberg on the investor call. "On mobile, we believe ads will be more like TV, hgh-quality and integrated into the experience, rather than off to the side."

Facebook reported a third-quarter net loss of $59 million as revenue rose 32 percent to $1.26 billion. The Menlo Park, Calif., company reported having 1.01 billion members, compared with 945 million in June 30.

Facebook’s performance on operations was profitable, although the $377 million operating profit was 9 percent below the prior year's $414 million. On an operating basis, there was net gain of 12 cents a share, a penny ahead of the analyst estimates carried by Thomson Reuters.

“People who use our mobile products are more engaged,” said Zuckerberg. “And we believe we can increase involvement even further.” The company also reported cash and investments exceeding $10.5 billion.

Analyst Brian Pitz at Jefferies, which didn't participate in Facebook's IPO, maintained a "buy" recommendation on Facebook but raised his price target to $32 from $30, mainly because of growth in mobile advertising.

"We are encouraged Facebook could deliver this kind of growth without much help from new products like Offers," he said. Pitz also liked the report that user engagement with the site had risen.

Monthly active users rose 26 percent from a year ago, nearly 60 percent of members logged in daily, and overall ad revenue rose 36 percent to $1.06 billion, more than the predicted $1.03 billion, Pitz said.

Meanwhile, COO Sheryl Sandberg offered examples of how Facebook's able to tap into the growing market. In Japan, she said, the Lawson convenience store chain ran a fried chicken promotion. More than 500,000 Facebook members responded almost immediately, 92 percent on their mobile phones, she said.

For Lawson, Sandberg said the promotion generated a 700 percent return on ad spending. In the U.S., Samsung Electronics (Seoul: 005930) mounted a massive campaign to sell its new Galaxy S III smartphones in the quarter and was hugely successful.

"We're a third thing," the Facebook COO explained. "We're not TV, we're not search. We are social advertising and I would say our clients are in different parts of the adoption curve."

She and Zuckerberg also said Facebook expects major gains in advertising, search and news ahead, as well as continued strength in games.

Comments like that prompted still another analyst, Arvind Bhatia of Sterne Agee, who already had a "buy" on the shares, to boost his estimates for earnings. For 2012, he raised estimates to 50 cents a share from 48 cents, while boosting estimates for 2013 earnings to 63 cents from 62 cents a share.

"Mobile advertising is already on a $1 billion run rate!" Bhatia said. "This is the single biggest takeaway from 3Q earnings."

Meanwhile, Facebook disclosed some data about where its members are around the world and how much revenue they generate.

The U.S. and Canada account for roughly 50 of revenue, while Europe accounts for about 27 percent and Asia for 12 percent. No surprise: the U.S. and Canada members generate the most revenue, or about $3.40 per average user compared to the total average of only $1.29 per user.

European users accounted for about $1.37 in revenue during the quarter while Asian users accounted for only 58 cents.

Meanwhile, CFO David Ebersman conceded one benefit of the collapse in Facebook shares: the acquisition of private photo apps specialist Instagram of San Francisco cost only $300 million, instead of the initial $1 billion value agreed by the company just ahead of the IPO. Most of the payment was for Facebook shares, rather than cash.

All three senior Facebook officials said Instagram added only a little new revenue during the quarter because it was only part of Facebook a short time. But Zuckerberg said that its users now exceeded 100 million, rather than the 27 million when the acquisition was announced.