Facebook began rolling out a new feature this week that resurfaces your old posts, pictures and status updates from a given day years in the past. The tool, called “On This Day,” looks and functions like the popular Timehop app that pulls and publishes social media content from a user’s past.

This kind of timeline digging has backfired on Facebook before. Late last year, the site came under fire for its “Year in Review” feature after it dredged up painful and unwanted memories for many users. One man, Eric Meyer, was forced to see photos of his deceased six-year-old daughter who passed away that year.

“Where the human aspect fell short, at least with Facebook, was in not providing a way to opt out,” he said at the time. “The Year in Review ad keeps coming up in my feed, rotating through different fun-and-fabulous backgrounds, as if celebrating a death, and there is no obvious way to stop it.”

Fortunately, users must opt in to On This Day before using it, meaning it shouldn’t spring any unpleasant surprises. Users who do choose to delve into their pasts will also get the option to share the old content with their friends or keep it private. But the tool is still a stark reminder that content shared on Facebook never truly goes away. As always, be careful what you post; you never know how it might come back to haunt you.