The dynamic remarketing tag collects data such as:
- affinity group characteristics
- number of code snippets
- business ID numbers of visitors
- types of pages viewed
Remarketing allows you to show ads to people who have previously visited your website or used your mobile app. Dynamic remarketing takes this a step further, letting you show previous visitors ads that contain products and services they viewed on your site. With messages tailored to your audience, dynamic remarketing helps you build leads and sales by bringing previous visitors back to your site to complete what they started.
The dynamic remarketing tag collects data, such as the IDs of the products or services that people viewed on your website, the types of pages viewed (such as shopping cart pages), and the total value of items. The AdWords system can use this data to remind people to take action
You can read more here: https://support.google.com/adwords/answer/3103357?hl=en