The recipient doesn’t get any identifying data about you, because the data that shows the link was clicked does not identify you as an individual, since it’s passed through privacy-preserving protocols.

To further clarify the exact data available to any party:

• The ad marketplace only knows that someone, somewhere clicked the link.
• Mozilla knows that roughly x users have clicked sponsored links overall.
• The company you went to from that sponsored link knows that your IP/browser visited at X time, and you clicked through a sponsored link from the ad marketplace

There isn’t much of a technical difference between this, and someone seeing an ad in-person where they type in a link, from a practical privacy perspective.

Their implementation is completely different from traditional profile/tracking-based methods of advertising.