It was nearly a year and a half ago that Facebook CEO Mark Zuckerberg, standing onstage at the company’s annual developer conference, announced that the company would begin letting users sever the connection between their web browsing history and their Facebook accounts. After months of delays, Facebook’s Clear History is now rolling out in Ireland, South Korea, and Spain, with other countries to follow “in coming months,” the company said. The new tool, which Facebook conceived in the wake of the Cambridge Analytica scandal, is designed to give users more control over their data privacy at the expense of advertisers’ targeting capabilities.
When it arrives in your country, the Clear History tool will be part of a new section of the service called “Off-Facebook activity.” When you open it, you’ll see the apps and websites that are tracking your activity and sending reports back to Facebook for ad targeting purposes. Tapping the “Clear History” button will dissociate that information from your Facebook account.
You can also choose to block companies from reporting their tracking data about you back to Facebook in the future. You’ll have the choice of disconnecting all off-Facebook browsing data, or data for specific apps and websites. Facebook says the product is rolling out slowly “to help ensure it’s working reliably for everyone.”
The company warned that users would likely see apps and websites in their account activity that they do not recognize. “For example, a website you didn’t visit could show up because a friend looked it up on your phone,” the company said. “Or because you share a home computer with your partner and kids.”
The Clear History tool was originally expected to launch last year. But as my former colleague Kurt Wagner reported at Recode, Facebook hit a number of unexpected delays. Here’s part of his interview with David Baser, the company’s head of privacy products:
Baser chalked up the delay to two technical challenges, both of which are related to how Facebook stores user data on its servers.
1. Facebook data is not always stored in the same way it is collected. When Facebook collects web browsing data, for example, that data set includes multiple parts, like your personal identifying information, the website you visited and the timestamp for when the data was collected.
Sometimes those pieces of data are separated and stored in different parts of Facebook’s system. Finding them all so that they can be cleared, especially once they’ve been separated, has been a challenge, Baser said.
2. Facebook currently stores browsing data by date and time, not by which user it belongs to. That means there was no easy way within Facebook’s system to see all the browsing data linked to an individual user. Facebook had to build a new system that stored browsing data categorized at the user level. “That was not very simple, actually, in practice for us to build,” Baser said. It’s an important element, though, because in order for users to go in and clear that data, they need to be able to find it.
“Since Off-Facebook Activity is a new kind of tool, there was no template for us to follow,” Facebook said in a blog post today. “Our engineering teams redesigned our systems and built a new way for them to process information. We also conducted months of research to get input from people, privacy advocates, policymakers, advertisers and industry groups. We made important changes in response to what we learned.”
Facebook plans to continue building similar tools as it attempts to reorient the company around privacy, it said in its blog post.