Customer Match a type of remarketing that will match your list of emails to Google users. Customer Match is a useful advertising tool and can help you reach your business goals. For example, if you were at a tradeshow collecting email you could upload a CSV file to Google AdWords and create a custom audience based on the email address. You can then run ads to the audiences that matched to Google users. Customer Match targeting is not cookie related, which means that you can still target your audience even when browser cache is cleared.