How remarketing works
Remarketing can help you reach people who have previously visited your website as they visit other sites on the Google Display Network or search on Google. Using remarketing, you can show these customers messages tailored to them based on which sections of your site they visited.
To start using remarketing, you need to add the remarketing tag, a small snippet of code that you get from AdWords, across all your site pages. Many sites have an identical footer for all pages, and this remarketing tag could be placed there.
Once you've added the remarketing tag to your site, you can create remarketing lists for any of your webpages. For example, you could create a remarketing list for visitors to your most popular product category. The remarketing tag tells AdWords to save visitors to your "Popular category list." When people visit that page, their cookie id is added to the remarketing list.
Then, you create an AdWords campaign with a specific message to show only to people on your "Popular category list" while they search on Google or browse other Display Network sites. Your remarketing messages won't be shown to people who are not on the list.
Because the remarketing tag is on all of the pages of your website, you can develop more detailed audiences. For example, you could create lists not only for your most popular product category, but also for each of your other product categories or your shopping cart.
People looking for diving suits visit your online store to check out the available types of suits. The site could add these shoppers to a "Scuba diving" list to show them ads about related products. Then, your ads can be shown to these shoppers while they browse other websites on the Google Display Network. Or, in case these shoppers are actively looking for diving suits, you can set a bid adjustment for this remarketing list on Google Search. Instead of showing these customers a standard ad about your store, you could show them an ad that offers a special discount on diving suits. This ad might encourage them to return to the website to buy a suit.
To use remarketing on the Google Display Network, you may want to choose "Display Network only - Remarketing" as your campaign type when you create your campaign. The default settings in this campaign type can help you achieve better performance by keeping your targeting broad enough but focused on the right audience. To use remarketing lists for search ads, you may want to select "Search Network only - All features" as your campaign type.
If you have a "Search Network only - Standard," "Search Network with Display Select," or "Search & Display Networks - Standard" campaign, you won't be able to add remarketing lists to your campaign.
As people browse certain Google services and websites that have partnered with the Google Display Network, Google stores a number in their browsers (using a "cookie") to remember their visits. This number uniquely identifies a web browser on a specific computer, not a person. Learn more about cookies.
A remarketing tag is a small snippet of code that you get from AdWords that you can add to your website to start using remarketing. Learn how to add the remarketing tag to your site.
Remarketing list definition rules
Once you've added the remarketing tag to your site, you can define lists for different sections of your site using rules. For example, if you want to define a list for a page of your site where you sell electronics, you can use this rule: "URL contains electronics."
With rules, you can create as many lists as you want without having to add more tags to your sites.
The remarketing tag also lets you send custom parameters that you can use to create your remarketing lists. An online store, for example, can send the product price and the page type (such as the purchase page) in the tag to create a list for people who bought any product above a certain price.
In this case, the custom parameters that the online store would include in the remarketing tag would be value (price of the product) and pagetype (type of page, which indicates how close to purchasing customers are).
Sensitive categories of sites can't use remarketing. If you're setting up a remarketing campaign and placing the remarketing tag on your site, you need to follow the Interest-Based Advertising Policy.