It's finally here. More than a year after Mark Zuckerberg took the stage at Facebook's 2018 F8 conference and announced plans to create a "clear history" tool that would let users remove browsing data from Facebook, the company has something to show for it.

After numerous delays, they're now starting to roll out the "clear history" feature. The catch? It doesn't actually "clear" any of your data at all.

Instead, the new privacy feature will allow users to "disconnect" their "off-Facebook activity" from their account, meaning their browsing data will be separated from their account information. This will help reduce some kinds of targeted advertisements, but it won't actually remove any of your data from Facebook's servers, or prevent the company from using that data. And Facebook will still track people who don't use its service at all.

In a blog post, Facebook engineers suggested the reason they opted to "disconnect" data rather than allow users to delete it entirely is because deletion would be too time-consuming and possibly unreliable.

"Attempting to delete information from various databases across many different tables and rows would take time and may not work reliably," the engineers wrote, referring to the way Facebook's data is stored. "The quicker, more reliable method would be to disconnect it directly from a person’s account."

Think about that: For Facebook, which holds more than $40 billion in cash and hires some of the best engineers in the world, actually removing users' data from its systems is simply too hard. (Not mentioned is the fact that Facebook also has little incentive do so, as it would disrupt its advertising business even more.)

Somewhat confusingly, the feature, which will initially only be available in Spain, Ireland, and South Korea, will still be labeled "clear history" in Facebook's app. The app will also let users view whatever browsing data the company has collected from websites that use Facebook's like button, login features, or pixel tracking. And you can opt to "disconnect" your future browsing activity from your account — though, again, this won't prevent Facebook from collecting data about your activity in the first place.

That all may seem like a bit of a letdown for anyone who was hoping "clear history" might finally allow them to take back some of their personal information from Facebook. But even though it's much more watered down than what some had hoped for, the new controls could have a significant impact on Facebook's advertising revenue.

That alone could be enough incentive for some Facebook users to enable the new privacy settings. But most of Facebook's 1 billion users won't have the opportunity to even do this for some time. The company says the feature won't be widely available for several months.

(责任编辑：资讯)