Facebook will let advertisers know where a promotion was first viewed and when it led to a purchase by tracking users between their electronic devices, a tool that may reignite privacy concerns.
Marketers will be able to see the number of users that clicked on an ad, whether they used a smartphone, tablet or desktop computer, and which device was used to buy a product, Menlo Park, California-based Facebook said in a blog post Wednesday.
Facebook has been bulking up advertising services as the social network's mobile ads propel revenue and profit. While users and privacy watchdogs around the world criticize Facebook's use of personal data, the company is under pressure from advertisers to prove that their mobile promotions are effective.
As Facebook finds new ways to analyze the behavior of its more than 1 billion users, controversy has emerged regarding its methods. A Facebook data scientist apologized in June after conducting an experiment that temporarily influenced what almost 700,000 readers saw on their news feeds without getting permission.
With the new cross-device service announced Wednesday, Facebook is aiming to prove that mobile ads can lead to purchases, even if those purchases aren't necessarily made on a smartphone. In a study with Altimeter Group, Facebook found that among people who showed interest in a mobile ad, more than 32 percent took action on desktop computers within 28 days.
