Facebook CEO Mark Zuckerberg made his first major public appearance since the social network's rocky May IPO.
Facebook became the first US company to debut on stock markets with a value of more than $100 billion.
Since then, however, it has since lost more than half of its capitalisation as investors fret about slowing growth and the company's challenges making money as users shift from PCs to mobile devices.
The 28-year-old co-founder asked Wall Street to be patient as the company developed new products, addressing issues such as employee morale, and dashing rumours Facebook may build a smartphone.
His comments helped drive Facebook shares up more than 3% after hours to above $20, building on an earlier 3.3% gain in regular trade.
The stock is still well off its $38 debut price.
Mr Zuckerberg, who has himself lost billions of dollars on paper since Facebook's market debut, admitted to disappointment about his company's crumbling share price, but argued Wall Street has yet to grasp the full potential of its fledgling mobile business.
"It was positive just to see him out there speaking," said Raymond James analyst Aaron Kessler. "He was hinting that the stock was undervalued, and we'll see about that. But he's looking at this business as a multiyear investment, even if investors are looking for results much sooner."
TechCrunch Disrupt's rapt audience
Speaking at the TechCrunch Disrupt conference in San Francisco on Tuesday, Zuckerberg highlighted Facebook's progress in mobile over the past six months and the company's room for growth.
Facebook's recently released mobile ads are already delivering better results for advertisers than the traditional "display" ads that appear on the right-hand side of the social networking service on PCs, Mr Zuckerberg said.
"One of the main things that I think is misunderstood right now is how fundamentally good" the company's mobile prospects are, he said.
While declining to offer details, Mr Zuckerberg hinted that the company was halfway through a cycle to "retool" and offer new advertising products.
Zuckerberg looks to search as growth area
He also said he believed search could be a ripe area of growth for Facebook and was working to offer a competitive search product, comments that likely interested executives at Google Inc, one of Facebook's fiercest competitors.
Facebook has a team working on the social network's existing search feature, which already garners roughly 1 billion queries every day, Mr Zuckerberg noted. But at some point he said Facebook would focus its efforts more intently on developing a full-featured search service, which he described as a "big opportunity."
Mr Zuckerberg, who wrote in the IPO prospectus that the company has always cared primarily about its "social mission," has kept a low public profile as the stock has crumbled in the months since the IPO.
Employee share sales add to downward pressure
Adding to the pressure on the stock is the ongoing expiration of "lock-up" selling restrictions for shares held by employees, insiders and early investors: More than 1 billion additional Facebook shares are set to become available for trading by year's end.
Mr Zuckerberg, who recently committed not to sell his own shares for at least 12 months, conceded that the company's downward-spiralling stock was not helping staff morale, but stressed he still thought it was a good time to join the company and "double down."
"It's not like this is the first up and down that we've ever had," he told hundreds of attendees at the conference. "I would rather be in the cycle where people underestimate us."
While Facebook has taken a beating on Wall Street, some of the Internet industry programmers, entrepreneurs and investors who packed the aisles to watch Zuckerberg's roughly 30-minute talk said their faith in the CEO and the company was not shaken.
"This company is about vision and changing the world and I don't know who would be better prepared to lead it than the guy who had that vision and built the company to a profitable multibillion dollar company before his 30th birthday," said Dave Crowder of GSV Asset Management, which owns Facebook shares.
Mr Zuckerberg acknowledged that he had erred years ago by using a programming language that slowed the development of Facebook apps for Apple and Android phones.
"Probably we will look back and say that that was the biggest mistake, the biggest strategic mistake we made," he said of the company's decision to create mobile apps using open web standards instead of building apps specially designed for iPhone and Android smartphones.
But he again quashed a years-long rumour that Facebook is wading into the hardware business and developing a branded phone.
Building a smartphone would be "clearly the wrong strategy for us," Mr Zuckerberg said.