Deduplication lets you control how often a tag runs for the same visitor, so you don't double-count conversions or run a tag more than you mean to. You set a marker when something happens, then add a deduplication condition so a tag runs only when the right marker is present or absent.
A marker is a client-side flag stored in a cookie in the visitor's browser. Markers are time-based and organized into groups. Each marker has a group, a name, and an expiry time. The expiry is checked each time the visitor loads a page, and an expired marker is removed.
A deduplication condition checks whether the visitor has a given marker before the tag runs. You can check for more than one marker at once.
Before you begin
You can only add a deduplication condition to an existing tag to make the tag run based on a marker. To create a tag first, see How to create and manage tags. For how conditions work in general, see Tag targeting rules.
Instructions
In Data Activation, navigate to Tags and select Pages.
Open the tag you want to deduplicate.
Click the pencil icon to configure rules.
Select the Deduplication rule.
Enter the marker group and marker name to check.
Save the rule.
Publish your changes to apply the rule on your site.