Facebook Inc (NASDAQ:FB) is likely rekindling privacy worries with its new plans to study users’ shopping habits across multiple devices. The social network says it will tell advertisers on what device shoppers first viewed the items they bought and then which device they were using when they actually purchased the item.

Shopping habits facebook

Facebook to share more info with advertisers

Facebook said in a blog post that advertisers will be able to see the devices on which people view their ads and then purchase their products. The social network emphasizes that in offering this feature, however, it never shares personal identity information with advertisers or tracks its users.

“For instance, a marketer can view the number of customers that clicked an ad on an iPhone but then later converted on desktop, or the number of people that saw an ad on desktop but then converted on an Android tablet,” the social network said in its blog post.

Facebook has been working on improving the data it provides to advertisers as its mobile advertising revenue make up larger and larger percentages of its overall ad revenue.

Facebook’s methods questioned

The company has been trying to balance privacy concerns with increasing the amount of user data it can provide to advertisers. So while users demand better privacy, advertisers are demanding that the company share more information about its users’ habits.

Facebook has been looking for more ways to analyze the habits of its over 1 billion users. However, controversy about how the company does provide data to advertisers. Meanwhile privacy advocates have been criticizing how Facebook uses personal data.

How Facebook will use cross-device data

With today’s cross-device analysis, the social network is trying to prove that its mobile ads do result in sales for advertisers—even if users don’t actually use their smartphone to make a purchase. Facebook found in a recent study conducted with Altimeter Group that 32% people who engage with mobile ads ended up following through on their interest by making a purchase on their desktop PCs within just 28 days.