What it is
You give Google a customer list, a CSV of hashed emails or phone numbers, and Google matches it against signed-in users to build an audience segment. That segment can then be used three ways: as a targeting audience, as an observation audience, or as an exclusion. Lists have a membership duration and need at least 100 matched, recently updated members to stay active.
The exclusion use most accounts miss
The most underused move is exclusion. Upload the leads your sales team already disqualified, spam, tire-kickers, competitors, repeat bot form-fillers, and apply the list as a negative audience so you stop paying to re-acquire people you have already rejected. Unlike targeting, which requires $50,000 of lifetime spend and 90 days of account history, using Customer Match for exclusions is open to every policy-compliant advertiser from day one. We walk through the whole play in our piece on excluding the leads your sales team already rejected. A customer list is also what tells Google who is new: new customer acquisition goal.
Common questions
Do you need a minimum spend to use Customer Match?
Not for exclusions. Any policy-compliant advertiser can upload a customer list and use it to exclude an audience. The $50,000 lifetime spend and 90-day history requirement applies only to using Customer Match for targeting and bid adjustments.
What can you upload to Customer Match?
First-party customer data you have collected, most commonly email addresses, and also phone numbers, mailing addresses, or mobile device IDs. Google hashes and matches it against signed-in users to build the audience.