Cookie syncing is the process used by internet advertisers to combine the profiles they have developed for the same user. The process is most commonly used to provide more detailed user profiles for real-time bidding auctions for advertising spaces on web pages in the user’s browser.

Cookies are domain specific, meaning that they are only relevant to the website that they have been created for. In order to make more powerful profiles of users, advertisers want to collect together as much information about the user as they can get. Although the advertiser may have been able to track a user across the internet using their own cookies placed on various websites, a more thorough picture can emerge by combining information with that gathered by other trackers. The technique of cookie syncing involves aggregating the information from the profiles created by more than one tracking firm.

In order for cookie syncing to work, advertisers must be able to find a match for the user they have a profile for in the profiles of the partner advertisers they are looking to sync with. After the match has been made, the information within the cookies are then shared between the parties. This process allows advertisers to create much more specific advertisements for the users they are targeting, with a more thorough profile encouraging higher priced bids in the auctions for the advertising space on web pages that the user visits.


Last updated: 15 March 2018