Facebook will start revealing which ads have been behaviourally targeted to users on the social network, in a bid to ease privacy fears.
The social network has agreed with the Online Interest-Based Advertising Accountability Program to start displaying the "AdChoice" icon in behaviourally targeted Facebook Exchange (FBX) ads.
However, the icon will only appear when users roll over a grey "x" above the ad.
The icon will this let them know the ad is marketed to them based on browser behaviour.
Crucially, the AdChoice icon will also let users opt out of that specific ad network.
Facebook will also replace the "Report this ad" hover text with a more descriptive phrase like "Learn about Facebook Ads."
In an emailed statement from Facebook, Chief Privacy Officer Erin Egan said: "At Facebook, we work hard to build transparency and control into each of our products, including our advertising offerings."
Users will start seeing the AdChoice implementation in desktop Facebook Exchange ads at the end of March.