Facebook’s new ad platform will help marketers track you by John Kell @FortuneMagazine September 29, 2014, 8:18 AM EDT E-mail Tweet Facebook Google Plus Linkedin Share icons Facebook officially debuted a new advertising platform known as Atlas, a business the social-media website has been rebuilding since it bought it from Microsoft last year. In a somewhat jargon-filled blog post, Facebook FB said it rebuilt Atlas “from the ground up to tackle today’s marketing challenges, like reaching people across devices and bridging the gap between online impressions and offline purchases.” More simply: the new advertising platform is designed to improve how marketers target and measure the ads they buy across the Web, according to a Wall Street Journal report earlier this month. And as Re/code points out: it will let advertisers buy ads, via Facebook, on properties Facebook doesn’t own. Facebook says Atlas delivers “people-based marketing,” saying marketers can target consumers across multiple devices with the rebuilt Atlas, which has a new code base, as well as a user interface meant to aid media planners and traffickers. Essentially, Facebook says the problem it is trying to solve is that today’s technology for ad serving and measurement–cookies–are flawed when used alone. Cookies don’t work on mobile (where consumers are spending a lot more time scrolling the Internet), and thus are becoming less accurate in demographic targeting and can’t easily or accurately measure customer purchase patterns. Facebook says it is welcoming a “key group of partners” to use Atlas, naming two in the main blog post: ad giant Omnicom OMC and Facebook-owned Instagram. There are also some murmurs that Twitter TWTR could be joining the platform.