Enhanced conversions

Both platforms describe the same machinery in almost the same words, which is usually a sign a definition has settled rather than a vendor writing a brochure.

Microsoft says enhanced conversions supplement existing conversion tracking using first-party data, and that first-party data is more reliable than third-party data. It then names the substitution directly: instead of using a third-party cookie with the Microsoft user ID, enhanced conversions allow the use of first-party information such as an email address or phone number. Google describes its version as supplementing the existing conversion tags by letting advertisers send hashed first-party customer data from the website in a privacy-safe way.

The part worth reading slowly is what the hash is compared against. Microsoft says it attributes hashed emails or phone numbers to the relevant ad campaign by matching advertiser data to user activity on Microsoft properties. Google says the hashed customer data is compared to hashed customer data of signed-in Google accounts. In both cases your customer is being looked up in the platform's own directory of account holders.

There is a prerequisite that decides whether this is even possible, and Microsoft states it plainly: first-party customer data, an email address or phone number, has to be available on the page where your conversion tracking tag fires. So it works on a confirmation page that knows who just converted, and not on one that does not.

Google publishes a figure for the benefit, and it is worth quoting as its own claim rather than as a finding. It reports that advertisers using first-party data alongside click IDs for offline measurement saw a median 10% increase in conversions compared with standard offline conversion imports.