If you have multiple domains that you want to use remarketing on, you can do it using one Google account. For example attorneys may segment their practice areas with different domains or perhaps they have different offices in different cities and have location-specific domains. Whatever the case, attorneys can run multiple remarketing campaigns using one account and some specific AdWords configuration methods.
When you create your remarketing campaign1, add the remarketing code that you generate to all of the domains where you will be running campaigns. Google does not regulate where the code is placed and we will be adding a filter later to tell Google which remarketing list should be used. Note that the filter is the important part here. Without proper filtering of lists, the same ads will be shown to all lists when they visit any site that the code is installed on.
Here is a great video from Google on adding the remarketing code to pages of your website:
You can create multiple remarketing lists in the shared audiences library inside your AdWords account. Wordstream has an excellent post2 on creating remarketing lists. By specifying a URL that you want Google to build a list of visitor cookies for, you can market to people based on the website (and even pages) that they have visited. This works in much the same way as other filter-based features in AdWords like negative keywords3 or location targeting.
To create a filter log into your AdWords account
Now all you need to do is associate that remarketing list with the remarketing campaign that it is relevant to. We go over in-depth how to develop a remarketing campaign here4. Once those things are done and the list has built up cookies from at least 100 visitors in the past 30 days, your ads will start showing for only those visitors who have gone to the URL you have indicated in the list.
As long as you have remarketing tags installed on all of your domains from the same Google account you are using for remarketing, you can specify those domains in various remarketing lists for different campaigns using rules. The main benefit here is that you can use one Google account to manage all of your campaigns in one location.
Other benefits include: