Announcing the new feature, Facebook noted that it is not yet available to all users, and will be rolling out globally over the next few days.
The On This Day feature will show you posts, photos, videos shared by you or tagged by others from the same date in the past years, all on a single page, unlike the curated video format in Look Back but similar to the timeline format of Year in Review.
Facebook's new On This Day feature will be accessible on both desktop and mobile in the bookmarks menu, search, News Feed stories, and also on a dedicated page - https://www.facebook.com/onthisday.
Once on the page, users can choose to subscribe to notifications so that they will get an alert whenever they have memories to look back on. Users will also be able to edit and delete old posts, or decide to share the memories with their friends, notes Facebook.
"For example, you might see past status updates, photos, posts from friends and other things you've shared or been tagged in - from one year ago, two years ago, and so on. Only you will see this content unless you decide to share it with your friends."
Just to remind you, this feature had previously rolled out to some users as a test in 2013. To see what has been improved, we will have to wait for the feature to roll out to us.