Ads Shown to the People on Your Customer List

What was announced

Google announced Customer Match yesterday. It lets an advertiser upload a list of customers' email addresses to AdWords and show ads to those people when they are signed in to Google and searching, reading Gmail or watching YouTube.

Until now, remarketing reached people through what they did on your website. Customer Match reaches them through an address they gave you.

For some businesses that is a useful new tool. For others the list is too small to use, or was collected on terms that do not stretch to advertising.

Three questions come before any upload: whether your customers would expect it, whether your business suits it, and whether your list is big enough.

How the matching works

The list is uploaded to AdWords as a file, and Google compares the addresses with the ones people use for their Google accounts. Only matches can be shown ads.

An address someone uses for Gmail, or registered as a Google account, can match. A work address, or an old one they never use with Google, will not.

Google says the addresses are hashed, a one-way scrambling, for the matching, and the business never learns which customers matched. It sees an audience, chooses where ads appear to it and sets bids, as with any remarketing list.

Which businesses it suits

• Repeat purchases on a cycle, such as season passes, servicing or refills.
• Seasonal businesses whose customers return each year.
• Long decisions, where people compare for weeks before buying.
• Lapsed customers worth reminding without another email.
• Existing customers left out of campaigns aimed at new ones.

The last is easy to overlook. A list of current customers can be excluded from a campaign for newcomers, so the budget is not spent on clicks from people who were coming back anyway.

Why a small list may be too small

Only part of any list matches, because many customers gave an address they do not use with Google.

On Search the audience shrinks again, since an ad appears only when a matched person is signed in and searching for one of your keywords.

And, as with its other audience lists, AdWords will not show ads to a list that is too small.

A local business with a few hundred addresses may find that what matches is too small to use at all. A list built over years, with thousands of customers on it, is a different matter.

The consent question

What follows is a general outline of privacy law, not legal advice on your own list.

Canadian privacy law, whether PIPEDA or a provincial privacy law, expects personal information to be used for the purposes people were told about when they gave it.

The Digital Privacy Act added to PIPEDA in June that consent is valid only if people would understand what they were agreeing to.

An address given for a receipt, or for a newsletter, was given for that. Whether uploading it to an advertising service fits depends on what customers were told.

A privacy page promising never to share customer information answers the question on its own.

Google's own rules for the feature also require the list to be your own customers' information, collected by your business, not a bought or borrowed list.

Tell customers first

The tidy way forward is to say it before doing it. Update the privacy page to say that customer email addresses may be used to show the business's ads on Google services, and how to ask to be left out.

Add a sentence saying the same where addresses are collected, at checkout and on the sign-up form, so new customers see it when they give their address.

Then honour requests to be left off, and take those addresses out of the next upload.

A worked example

A tobogganing hill on farmland outside town opens its groomed runs from the first good snowfall until the thaw. It rents toboggans, runs a warming hut and a snack bar, and sells day tickets and season passes online.

Over several winters it has collected the addresses of pass holders and online ticket buyers, and sends a newsletter when the hill opens and when passes go on sale.

When Customer Match was announced, the owners asked whether to upload the list before the pass sale in November. The checkout had said addresses were for tickets and hill news; the privacy page said nothing about advertising.

So the privacy page and the checkout wording were updated first, with a way to opt out.

The upload will include only buyers who have not unsubscribed, and anyone who has already bought this winter's pass will be left out of the pass campaign.

The plan is a YouTube and Gmail campaign in November aimed at last season's buyers. Whether enough of the list matches will only be known once AdWords has processed the upload.

Who to leave off

Anyone who has unsubscribed from your emails, or asked not to be contacted, should not be in the upload. They have told you how they feel about hearing from you.

Leave off addresses from contest entries and trade show draws, which came from people who never bought anything, and addresses so old they belong to an earlier version of the business.

And refresh the list on a schedule, since it does not update itself when someone unsubscribes.

Handling the file

A file of customer email addresses is personal information. Export it, upload it and delete the copy, rather than leaving it in a downloads folder or emailing it to whoever manages the account.

If an agency runs your AdWords, agree how the list is handled, and that it is removed when the agency stops working for you.

The counter-case

For a small local business with a modest list, Customer Match is likely to be more setup than result. The email itself, sent well, reaches the same people more directly, and remarketing to site visitors needs no upload at all.

For a business with a large list of customers who buy again, though, it is worth a careful trial: tell customers first, upload only people who still want to hear from you, and check the list is big enough.

Before uploading a list

1. Read your privacy page as a customer would.
2. Update it and your sign-up wording first.
3. Offer a way to be left out.
4. Remove unsubscribes and non-customers from the file.
5. Upload, then delete every local copy.
6. Check the matched size before building campaigns.
7. Refresh the list on a monthly schedule.

Step one decides everything else. If the privacy page promises never to share customer information, the answer is no until it says otherwise and customers have been told.

Whether the people on the list agreed to hear from you at all is covered in a checkout that signs customers up automatically.

Frequently asked questions

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