Remarketing on the Google Display Network: a setup guide

You place a small snippet of JavaScript from AdWords on your site. When someone visits, Google sets a cookie in their browser and adds them to one or more lists you have defined. You then build a display campaign targeted at those lists. When the visitor later reads a news site, checks the weather or watches a video on YouTube, your ad can appear. Lists can hold people for up to 540 days, and a list needs at least 100 active cookies before ads will serve against it.

Two options exist for the tag. The AdWords remarketing tag has been available since 2010 and in March Google simplified it to a single site-wide snippet, with lists defined by URL rules inside AdWords. In June Google began rolling out remarketing from within Google Analytics: a one-line change to your Analytics code lets you build lists from any Analytics segment, such as visitors who spent more than two minutes on the site or viewed three product pages. If you can get into that beta, use it.

Remarketing fails when it is one list called "All Visitors" with one ad. Define audiences by intent and by stage.

Then combine them. "Cart abandoners minus converters" is your highest-value audience. "All visitors minus product viewers" is a low-intent group that deserves a lighter touch and a smaller bid. If you run Analytics remarketing, add behavior lists such as "visited twice in 30 days" or "spent more than three minutes," which tend to outperform URL-only lists.

Keep durations short for high-intent lists. A visitor who abandoned a cart ten days ago has either bought elsewhere or lost interest; keeping them in a 90-day list wastes impressions and irritates people.

1. In AdWords, go to Shared library, Audiences, and create the remarketing tag. Place it before the closing body tag on every page, including thank-you pages. If you use Analytics remarketing, replace the ga.js line in your tracking code with the dc.js version instead.
2. Define your lists by URL rule or Analytics segment.
3. Verify with the Google Tag Assistant extension for Chrome or by checking that the list size in Audiences begins to climb within 24 to 48 hours.
4. Update your privacy policy. AdWords policy requires that you disclose the use of cookies by third-party vendors including Google, explain that ads are served based on prior visits to your site, and link to the Google Ads Preferences Manager and the Network Advertising Initiative opt-out page.
5. Check your pages against the sensitive categories policy. Health conditions, financial status, sexual orientation, religious belief and some others are off limits for remarketing lists.

Build remarketing as its own campaign on the Display Network only, never mixed with search. Then set these deliberately.

Frequency capping. Without a cap a visitor can see your ad 50 times in a day. Start with 3 to 5 impressions per user per day at the campaign level and adjust by list. Short, high-intent lists can tolerate more; broad lists should see fewer.

Bids by list. Bid highest for abandoners, moderate for product viewers, lowest for all visitors. Cost per click on remarketing generally lands between $0.30 and $1.00, so a 2 to 3 times spread between lists is normal.

Exclusions. Exclude converters from every acquisition list. Exclude placements that waste money: mobile apps and games are the usual culprits, and you can exclude the adsenseformobileapps.com placement in one step. Review the Placements report weekly for the first month and block anything with high impressions and no conversions. Use category exclusions for parked domains, error pages and content you would not want next to your brand.

Location and language. Match your service area. A local business should restrict to its metro area; national retailers should still exclude states they do not ship to.

Ad scheduling. Rarely needed for remarketing, but if your phone is the conversion point, consider daytime only.

Conversion tracking and view-through. Install AdWords conversion tracking on your thank-you pages and watch both click conversions and view-through conversions. View-through numbers are inflated by default; a 30-day window counts anyone who saw an ad and later converted for any reason. Shorten the view-through window to one or seven days for an honest read.

Display creative is where small advertisers underinvest. Text ads do serve on the Display Network, but image ads win the auction far more often and perform better.

• Cover the main sizes. 300 by 250, 728 by 90, 160 by 600 and 320 by 50 reach the large majority of inventory. Add 336 by 280 and 300 by 600 if budget allows. The Display Ad Builder in AdWords will produce acceptable ads from your logo and a product image if you do not have a designer.
• Match the message to the list. Abandoners should see the product or category they left, perhaps with free shipping or a deadline. All-visitors lists should see the brand and the main benefit. One generic ad for every list halves your results.
• Rotate and refresh. Two to three variations per size, rotated evenly for the first month, then optimized. Replace creative every six to eight weeks; response falls as people tune it out.
• Land on the right page. Send abandoners back to the cart or the product, not the home page. A dedicated page for a remarketing offer usually outperforms a generic one.
• Keep the brand consistent. The ad, the landing page and the site should look like the same company. Visitors recognize you from the earlier visit; make that recognition instant.

Across the accounts we manage, remarketing campaigns typically deliver click-through rates between 0.2 and 0.5 percent, several times a cold display campaign, and cost per acquisition at or below search for the same business. Budget is bounded by traffic: a site with 10,000 visitors a month will build lists that can usefully absorb perhaps $500 to $1,500 a month before frequency climbs and returns fall.

Measure it on click conversions first, view-through conversions on a short window second, and overall account conversion rate third. If search conversions rise after remarketing starts, that is partly the point; people come back by searching your brand. Review the Placements report, the frequency distribution and list sizes every two weeks for the first two months.

• One list, one ad, no cap.
• No converter exclusion, so you pay to show ads to people who already bought.
• Tag only on some pages, so lists are smaller than traffic.
• No privacy policy update, which is a policy violation and a trust problem.
• Judging the campaign on 30-day view-through conversions alone.
• Leaving mobile app placements on and wondering why clicks never convert.

Discover: we audit your site's traffic, your conversion points and your existing AdWords and Analytics setup, and look at where visitors drop out. Plan: we define the lists, durations, caps, bids, budget and privacy changes in one document before anything is built, with targets for cost per acquisition by list. Build: our performance marketing team installs the tags, builds the campaign and the creative in all the key sizes, our web team updates the privacy policy and builds landing experiences for the high-intent lists, and the brand team keeps the ads consistent with the site. Improve: we review placements, frequency and conversions every two weeks, refresh creative on a schedule and expand to new lists as traffic grows. Because brand, growth, web and technology sit on one team, the tag, the ad and the page it lands on are built as one system.

The Product Launch engagement is the representative pattern for this work. A launch produces a wave of first-time visitors who are interested but not ready to buy, and remarketing was built into the plan from the start: lists segmented by which product pages people viewed, short durations for the high-intent groups, creative that continued the launch story rather than repeating it, and strict exclusion of anyone who had already purchased. Reporting separated click conversions from view-through so the team could see what the campaign was really adding.