Cookie syncing (synchronization), also known as cookie matching, is a process that helps different adtech partners store data in web browsers so that users can automatically synchronize the browser data from one device to another.
A small piece of information in a text file is stored in a wide range of collective data from users activity behavior to language, location, email address, name, etc., on your browser.
In this article, I’ll explain what cookie syncing is. How does it function? Why are AdTech and data businesses using it?
So let’s get started!
What is Cookie Syncing?
Cookies are domain-specific. Thus, one ad-tech partner’s cookie cannot be read by another’s. Assume a user visits your website, and you use a cookie to save information (interests, age, location, and so on) for that user.
Similarly, your third-party analytics providers and adtech partners (e.g., ad networks, SSPs, ad exchanges, DMPs, etc.) utilize their own cookies to store user data and re-identify the same user.
Now, when the same user visits another website with the same adtech partners, their cookie IDs can be used to identify them. But what about DSPs who do not have direct access to the website? How are they going to identify the individual and position the right bid? This is where cookie syncing comes.
Cookie syncing is a technique that allows adtech partners (SSPs, DMPs, CDPs, and DSPs) to synchronize their cookies and communicate including user data from various websites with one another.
As a result, DSPs can learn about the user’s interests, demographics, and geography and send a bid response with the appropriate bid and ad creative.
Also read: Cookie Theft: How to Guard Your Systems from Cyber Threats?
Different Types of Cookies
First-Party Cookies
First-party cookies are those produced and stored on websites that users visit regularly or often.
These cookies are domain-specific, which means they are only accessible to the website that created them.
Visitors to these websites can utilize first-party cookies to improve their experience with tailored features.
First-party cookies provide numerous purposes for the user’s surfing experience. They can remember your selected language, font size, color scheme, and area when browsing.
They can also save your login information, checkout information (such as your name, address, and payment methods), and shopping cart items. This not only frees up space in the cookie but also allows advertisers to collect and analyze additional user information.
Source: First-Party & Third-Party Cookies
Third-party cookies
What are third-party cookies? They are cookies created and stored by domains other than the ones users visit.
These cookies are not domain-specific, so they can be accessible by numerous websites using the same third-party service. These cookies are typically created using javascript code contained in web pages.
Third-party cookies follow your browser history and gather information about your interests and preferences.
They assign you a unique identification known as a cookie ID, which is used to establish a user profile based on your online activity.
They keep track of the websites you visit, the pages you view, the links you click, and so on. This allows businesses to provide tailored adverts to you in the future.
From Cookie to User IDs
While cookies can perform a wide range of purposes, their size limits their ability to carry large amounts of content. To remedy this issue, some cookies now only include a unique identifier.
By putting a cookie with a unique ID on the user’s computer, advertising and other companies can then store the remainder of the user’s information on their own servers. This not only frees up space in the cookie, but also allows advertisers to collect and analyze additional user information.
Key point: Some cookies now only carry a User ID, while the remainder of the user’s information and data is sent to the advertiser’s database.
How Does Cookie Syncing Work?
Let’s say a user, Sam, visits example.com, a website with an ad exchange called AdEx. AdEx can put a cookie on Sam’s browser to recognize her later. This cookie might be something like “Sam001.”
When an ad auction starts, AdEx sends bid requests with Sam001 to a demand-side platform (DSP) called BidPartner. Since BidPartner doesn’t know who Sam is, they create their own ID for her, say “SamA23.” The bid value might be low because the DSP doesn’t know much about her, so the ad might be less relevant.
Later, Sam visits another site, lifestylezone.com, which also uses AdEx. This time, AdEx recognizes her as the same person from newsdaily.com. AdEx works with BidPartner to sync their cookies—Sam001 and SamA23. Now, they both know that these IDs are for the same person.
Thanks to cookie-syncing, BidPartner knows more about Sam, so they can bid higher for her attention, offering more relevant ads.
Here’s how this typically works in real-time bidding (RTB) auctions:
When Sam visits example-site.com, an SSP (supply-side platform) places a cookie with a unique userID on her browser. The SSP might send a cookie-sync pixel from a DSP.
When the cookie-sync pixel loads, the DSP sets its own cookie with a userID.
Later, the DSP initiates cookie-syncing by redirecting to an endpoint given by the SSP. The endpoint looks like this: https://cookiesync.ssp.net/[dsp_id]?user_id=[user_id].
The DSP passes its userID in the query string, where dsp_id is the SSP’s internal ID for the DSP, and user_id is the DSP’s userID.
The SSP reads its cookie to identify the user and stores its userID along with the DSP’s userID in a “match table.” When the SSP sends a bid request to the DSP, it checks if there’s a matching userID. If there is, it includes that ID in the bid request to the DSP.
This way, multiple DSPs can sync their cookies through a series of redirections. Without cookie syncing, publishers and advertisers would have a harder time targeting users with relevant ads.
What Are the Benefits of Cookie Syncing?
There are various advantages to cookie synchronization.
- Retargeting
It is nearly impossible to retarget users without cookie syncing. The approach allows advertisers to place a cookie in the user’s browser when they first view the product page.
When a person visits your website or any other website, the advertiser uses cookie syncing to identify the same individual and offer the appropriate ad.
- Exclusion of Converted Users
Why would advertisers want to pay for customers who have once purchased their products or services? It makes no sense to serve such adverts to a converted user.
This is why cookie synchronization is necessary. It allows you to target such users, cease providing advertising, and only target users who have not purchased the products/services yet.
- Interest-Based and Demographic Targeting
Many advertisers require interest-based data and demographic information from consumers in order to segment audiences and offer appropriate adverts.
For example, when a user navigates different online pages, the publisher can collect the terms or keywords that the user looked for. The information of these users is shared with advertising through cookie syncing.
What are the Disadvantages of Cookie Syncing?
Cookie syncing has several advantages, but it also has some disadvantages.
- Latency
SSPs, ad exchanges, and DSPs rely largely on cookie-synching, which creates page delays and may result in a poor user experience. According to ID5’s cookie syncing (user-syncing) analysis, third-party redirection takes a standard of 19 seconds to load and wastes 0.8 MB of bandwidth (equal to a 15-second video ad).
Also read: Network Latency: Causes, Impact, and Reduction Strategies
- Privacy Flaws
Third-party redirects may expose publishers to data leaks and privacy concerns. According to a recent survey mentioned above, 81% of publishers had vendors recognized as potentially harmful to the brand, and 58% of vendors registered with IAB TCF did not include the gdpr_consent parameter in their settings.
- Data leakage
Cookie synchronization and third-party redirects placed in ad creatives can result in data leaking. In the same study, it was shown that some vendors had no direct interaction with publishers yet were able to monetise their branded audiences.
Wrapping up
Digital advertising requires the use of cookie synchronization. Through the sharing of user data, it makes it possible for various advertising platforms to present more tailored and relevant advertisements.
Advertisers can increase the efficacy of their campaigns while also benefiting from an improved user experience through the presentation of relevant advertising. A less accurate ad targeting would result in a worse user experience and less successful results for advertisers in the absence of cookie syncing.
FAQs on Cookie Syncing
How is ad targeting enhanced by cookie syncing?
Ad networks can identify the same person across various websites with the aid of cookie syncing. This enables them to exchange information and build a more thorough user profile, which improves the accuracy of ad targeting by taking into account demographics, hobbies, and online activity.
Is it possible to stop cookie syncing?
Yes, you can use browser extensions made specifically for privacy or change your browser’s settings to prevent third-party cookies from synchronizing cookies. Cookie syncing’s negative effects on your online experience can be mitigated by using the tools that many websites offer to opt out of targeted advertising.
Is cookie synchronization a privacy concern?
Cookie synchronization raises privacy concerns because it entails sharing user data across many platforms. However, credible organizations adhere to privacy standards and user permission policies to guarantee that cookie syncing occurs in a clear and legal manner.
