SAN FRANCISCO — Facebook is able to track its 1.3 billion users on desktop computers, mobile devices and other websites. Now, advertisers will be able to do the same, using the social-networking service’s data.

SAN FRANCISCO — Facebook is able to track its 1.3 billion users on desktop computers, mobile devices and other websites. Now, advertisers will be able to do the same, using the social-networking service’s data.


The technology, called people-based marketing, is the main feature of Facebook’s revamped Atlas ad server that will be shown to marketers this week in New York. Advertisers will be able to measure how often an individual — whose identities are kept anonymous — sees their ads, no matter what device they’re using, and tailor promotions based on the information.


As people expand their Internet activity to include mobile phones and applications, advertisers are seeking better ways to target them and make sure that the right promotions are reaching the right people. Atlas gets data from what people reveal on the social network, and from the other sites where they log in using their Facebook credentials. It’s an improvement compared with the "cookies" that track activity within a single Web browser.


"There is just a huge shift to mobile and we’re capitalizing on it by offering personalized marketing," Facebook Chief Operating Officer Sheryl Sandberg said in an interview. "Facebook has been built around people and focused on people since Day One."


Facebook has set up meetings to pitch the top advertising agencies on the new product in the next few days in New York, during Advertising Week, the industry’s annual gathering, according to David Jakubowski, Facebook’s head of advertising technology. Omnicom Group will be the first to use the product, through clients PepsiCo and Intel.


"You can get the right person at the right time on the right device," said Jonathan Nelson, chief executive officer of Omnicom Digital. "It’s going to shift dollars, from more broadcast-oriented stuff to more finely tuned messaging."


One added benefit of Atlas: the ability to use Facebook data to target users of Instagram, the popular photo-sharing application it acquired in 2012.


"It opens up a whole new opportunity for publishers on Instagram," Jakubowski said. "If you’re running ads on Instagram and use Atlas you can see who saw them, and if they bought something."


While the new product may spark privacy concerns because it tracks users’ activities, Sandberg said marketers won’t be given access to any data beyond what members have made available through their privacy preferences. The Menlo Park, California- based company this year started prompting users to look at their settings and change them if they revealed more than they wanted to.


"This year we did people-based privacy controls, and we’re doing people-based marketing," Sandberg said. "This doesn’t tell marketers who you are, and when Atlas uses Facebook data it honors the Facebook preferences of the user."


Facebook is expanding its advertising initiatives outside its main application. Earlier this year, the company opened up its network of advertisers to software developers who were given the option of running Facebook ads on their applications. Facebook recently agreed to acquire LiveRail, which will help it serve video advertisements outside of Facebook itself.


Optimism over Facebook’s advertising prospects have fueled a 44 percent surge in the stock price price this year, giving the company a market capitalization of $203.9 billion. Facebook reported a 61 percent increase in second-quarter sales to $2.91 billion. Mobile promotions accounted for 62 percent of ad sales, up from 59 percent in the prior period.


Instagram has also been ramping up its advertising capabilities for almost a year, with Omnicom as the main partner. Omnicom has spent hundreds of millions of dollars with Facebook on various digital efforts, Nelson said. The company spent months organizing its database to work smoothly with Facebook’s data, with the expectation that more dollars would shift to their offering, he said.


"I think this is really going to open up mobile for advertisers," Nelson said.