This new Facebook feature is called Facebook Notifications and was added to Facebook Login.
Facebook Login is a system through which users can use their Facebook account to log into third-party apps and websites, instead of creating a new account on that service.
Starting this week, Facebook users will get a notification in their Facebook app, on the Facebook website, and via email whenever they log into a third-party app or website via the Facebook Login feature.
The notification is meant to help users detect unauthorized access or use of their credentials, but will also help educate users about the data they're sharing with these apps.
Facebook says it specifically designed these notifications to also list the type of data a third-party app or website is harvesting from the user's Facebook account.
The idea is to allow users to understand what data is shared, limit a third-party app's access to some of their data, or stop using that app entirely.
"The design and content of the Login Notifications remind users that they have full control over the information they share with 3rd party apps, with a clear path to edit those settings," said Puxuan Qi, a Software Engineer at Facebook.
To help users take immediate action against any abuse, Facebook has added an Edit button in these notifications that will let users revoke any app/website's permission to access their data.
The feature is already live and Qi said Facebook will continue to improve it throughout the year.
This new feature is just the latest improvement Facebook is rolling out to its service following a series of privacy scandals over the past three years. Many of those incidents have been caused by third-party apps that mass-collected data on Facebook accounts and then abused the data for political campaigns, accidentally leaked it online, and mismanaged it, in general.
One way through which Facebook has fought back against misbehaving third-party apps has been by expanding its bug bounty program and allowing security researchers to hunt down misbehaving apps.
The login notifications feature rolled out this week is just another measure that passively reminds users about the data some of these apps are currently having access to.
Facebook's worst privacy scandals and data disasters