No Cookies? No Problem.

No Cookies? No Problem.

Mar 20, 2022 David Deppner

As more web browsers and platforms like Apple's iOS block cookies and conversion tracking, Google is pushing forward with other methods of conversion tracking and audience targeting. Their new system helps to build up the performance of ad accounts in a world that is increasingly concerned about privacy.

When people use Google’s search platform, they are consenting to Google’s terms and conditions. Google also often knows people’s email addresses because they are logged in to those services. Google also provides settings that allow users to opt-out of any remarketing ads. For people who haven’t opted out, but who are logged in, Google knows which email addresses performed which searches and clicked on which ads. On our end, we know if someone with a given email address is on our email marketing lists or if someone with a particular email address has made a purchase.

Google won’t share those email addresses with us, and we also typically can’t share those email addresses with Google. So, they came up with a system to allow us to figure out if we have email addresses in common, that we can use to enhance the accuracy of conversion tracking and add people to audience lists for future ad targeting on Google search.

The way it works is simple. We take an email address and transform it into a unique string using a one-way cryptographic hash function (SHA-256). This is the same system that is often used to securely encrypt passwords so they cannot be decrypted. This function is “one way” in that you cannot reverse it. Once we have this “hash”, we can compare it with Google’s hashes, and determine if there are matches or not. We are able to determine if we have a match, without exchanging any personally identifiable information.

So, for example, Google has your email address you@yourdomain.com in their system and has hashed that to the string “6c6d62ca9afded75c96053fa3bbc607309ea89493fd565310ea8a573781c958e”. If I perform a search and click through to the website and have cookies blocked on my web browser, there is no way to add me to a cookie-based audience. If I purchase, there is no way to add me to an audience of past purchasers built with cookies. And in many situations, there is no way to match my purchase back to the ad click to give credit in Google Ads for that ad click resulting in a sale (ALL conversion value from ads is being under-reported now because of this).

But if we take that purchase record and do our own hash of you@yourdomain.com to the string “6c6d62ca9afded75c96053fa3bbc607309ea89493fd565310ea8a573781c958e” we can pass that over to Google in something like a game of Go Fish.

“I have 6c6d62ca9afded75c96053fa3bbc607309ea89493fd565310ea8a573781c958e, do you?”

Google won't actually give us a straight answer on that, because they won’t reveal anything that can be traced back to an individual user. But if we tell them a hash string for a user that they know clicked an ad, and we tell them that user made a purchase, then they will update their conversion data to confirm that sale came from an ad click. And if we give them a big list of these, they will add users who match to audience targeting lists and allow us to target those users in the future.

We can never identify individuals with this method, but we can create audience lists of people who are on our email newsletter lists, past purchasers, and so on, and those people tend to be more valuable to advertise to over time.

Here is information on how Google uses the hashes: Google Ads Help: How Google uses Customer Match data

Here’s a brief overview of how this works for creating audiences: Google Ads Help: About the customer matching process

And here is a brief overview of their new program to enhance conversion tracking using this method: Google Ads Help: About enhanced conversions

I’m particularly excited about using this system to improve conversion tracking, because as cookie blocking becomes more common, we’re losing key information about which actions lead to sales that is core to the ongoing optimization of ad accounts, in addition to reported sales undershooting what is actually going on. If we can improve that accuracy as much as possible, it helps in being more efficient with achieving returns as well as accurately reporting on those results.

But also, many competitors are not using these systems because there’s more complexity involved in these integrations. So, there’s a competitive advantage aspect to this as well. If we have better information for bidding in the ad auctions, we can outperform competitors who don’t set-up these systems and gradually push their results down as ours go up. Getting as many of these systems set-up and configured right as soon as possible is key to building a longer-term strategic advantage.


Psyberware specializes in managing online advertising for ecommerce businesses, and nothing else. If you'd like to work with an agency that truly understands how to achieve profit in the current environment, get in touch with us.

Previous Post