Remarketing with GA allows advertisiers to create remarketing lists using GA’s dimensions & metrics. Now it is possible for a deeper remarketing integration between AdWords and Google Analytics. This integration helps retailers to have access to detailed product level reporting. Dynamic remarketing considers each customer as unique & ads can be created connecting visitors with their past shopping experiences on the site. As the ads are based on users past actions, these ads will perform better.
Steps for Dynamic Remarketing
1) Create remarketing lists using GA
2) Update your tags to track Product ID, Cart Value, and Page Type as custom variables (or dimensions)
3) Enable the Dynamic Link in Admin > Property > Dynamic Attributes.
4) Create a Dynamic Remarketing Display campaign in AdWords
Google Analytics Solutions Gallery has a remarketing starter list and can be downloaded from there.
Source: Google Analytics Blog