Facebook, Twitter Execs Talk Advertising at D11

The D11: All Things D conference hosted two of the most powerful executives in social advertising: Facebook COO Sheryl Sandberg and Twitter CEO Dick Costolo. They both addressed how they're embracing the mobile format to make ads that are more engaging, and valuable to both brands and advertisers.

Sheryl Sandberg on Mobile

Though the interview kicked off with a conversation about why Sandberg wrote 'Lean In' to reverse gender inequality, the conversation focused on Sandberg's role overseeing all parts of Facebook's business. And she said Facebook's attention is firmly focused on all things mobile. Why? Facebook has one in seven minutes of all the time people spend on the desktop, but one in five minutes of the time they spend on mobile devices. And they're checking

As for the question of whether the launch of mobile super-app 'Home' fell flat, Sandberg says it's just the first version, and very early days. She says that consumers either love it or hate it, but that the potential is there to transform phones, and make them more "social" and "people oriented. But she acknowledged that it's still "very early" and "it'll be a long road."

Michael Wuertenberg | World Economic Forum

Sheryl Sandberg at the World Economic Forum in Davos, Switzerland.

Sheryl Sandberg on Ads

Sandberg's optimism about Facebook's ad potential comes down to the fact that the company can have narrow focus but also a wide reach, and most companies only offer one or the other. ""We have a Super Bowl every day in the U.S.," Sandberg says, when you combine mobile and desktop audiences. She sited the example of Samsung launching a new phone with Facebook ads, saying it had a return on investment of thirteen times other Internet ads.

Sheryl Sandberg on New Revenue Streams

It's all about prioritizing, Sandberg says, in order to not be distracted by the many things the company could be doing. She acknowledged that while an ad network is a good idea, it's not a goal right now. As for search, she wouldn't announce anything, but said they're continuing to tweak it. And she left the door open to incorporate hashtags down the line.

Sheryl Sandberg on Facebook's 'Mombook' Problem

In the face of criticism that Facebook's losing its cool factor and teens are turned off by their parents joining the service, Sandberg returned to comments from Facebook's earnings call, saying "it's not a zero sum game." She acknowledged that kids are spending more time on Twitter and Tumblr, and even called temporary sharing services like Snapcaht "very important." But, she wouldn't make any announcements-- for now.

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Dick Costolo, CEO of Twitter.

Dick Costolo on the Future of TV

Twitter is doubling down on the TV space, because Costolo says "we've recognized that Twitter is the second screen for TV and TV is more fun with Twitter," calling Twitter the "social soundtrack for TV." So Costolo says the company is working to be "complementary to broadcasters in a world where they've come to think of tech companies as competitors.... So the notion of this is an instant replay of what's going on in sports right now, goes out as a tweet, it's in the fabric of it, it's great for broadcasters, it's great for us, great for users."

Dick Costolo on the Value of Twitter Ads

Twitter wouldn't detail anything about its advertising business' results, just saying it's "doing great." He cited examples of Bonobos, saying its ad spend was 13 times more effective than its other online marketing ad spend, and that Oreos say 10 percent higher purchases.

Dick Costolo on Innovation

The comment that drew the biggest gasp from the audience was the fact that Twitter takes bold steps to drive *fast* innovation amongst its engineers. He says that when developing for mobile, in order to encourage innovation, the company allows developers to test new features with one percent of users without getting approval from senior management or legal."

He says Twitter's biggest problem is its lack of simplicity, the fact that its "remarkable language" is hard for newcomers to understand.

—By CNBC's Julia Boorstin. Follow her on Twitter: @JBoorstin