Facebook has launched a new online advertising service that target users on any website using their Facebook details. 

Called Atlas, the service is designed to take on Google Ads Account Login's lucrative AdWords service.

It will allow Facebook to sell ads that 'follow' users across the web and mobile devices.

'We are bringing all of the people-based marketing functions that marketers are used to doing on Facebook and allowing them to do that across the web,' David Jakubowski, Facebook's head of advertising technology, said in an interview with the .

For instance, Atlas advertiser Pepsi could use Atlas to advertise one of its products on a sports site or a game app that is not affiliated with Facebook.

Atlas head Erik Johnson said the platform offers an advantage for marketers over most current ad-serving systems, which rely on cookies.

Cookies are used to track browsing on desktop computers, but they don't work for mobile devices - a growing source of Internet traffic.

'Cookies don't work on mobile, are becoming less accurate in demographic targeting and can't easily or accurately measure the customer purchase funnel across browsers and devices or into the offline world,' he wrote. 

Atlas solves that problem by tracking people based on their Facebook log-in information.

Advertisers using the platform can then request that their ads be targeted to a specific subset of users - for example, young people in the suburbs using mobile devices. 

The firm has already signed up its first customers.

'We're excited to announce that Omnicom is the first holding company to sign an agency-wide ad serving and measurement partnership with Atlas,' it announced today.

'Together, Omnicom - powered by Neustar technology- and Atlas will jointly develop integrations to enable more automated capabilities for Omnicom's clients, including Pepsi and Intel - who are among the first testing the new platform.'

Tech blog

Atlas is a former Microsoft property that Facebook bought last year for around $100 million that Facebook says it has now rebuilt from the ground up. 

It is distinct from Audience Network, a mobile ad network Facebook introduced in April that was aimed at app developers.

In contrast, Atlas is an alternative to Google's AdWords, which will let advertisers follow users across the web and mobile devices.

The blog presents Atlas as the solution since it uses 'people-based marketing.'

While the move might discomfit some users who are suspicious about how Facebook employs their personal data, it presents a new option for advertisers and an alternative to Google.