Email’s Biggest Value for Marketers? Consumer Identifier

When email first emerged, marketers jumped at the opportunity to send messages directly to customers and potential customers—eliminating print and postage costs and introducing automated measurement via clicks, opens, and on-site conversions. Few, if any, realized that—a quarter of a century later—email’s biggest value would turn out to be the address itself.

Today, as third-party cookies and device identifiers are driven away by browser changes and privacy laws, the email address remains the most stable and platform-independent identifier.

Email’s Capability in Identity Resolution

For years, identity resolution providers have utilized email addresses as a primary persistent identifier that connects various datasets, both offline and online, to build and connect user profiles to other profile identifiers and attributes—the goal being a lift in return on advertising spend (ROAS) for the media buyer across all channels, and an overall improvement in the ability to provide personalized experiences to customers.

More recently, the Trade Desk and others have been using hashed or encrypted email addresses as a key to create anonymized user IDs to solve for addressability post-third-party cookie. Using tools like UID 2.0, publishers and advertisers can connect first-party audiences accurately and at scale, leaving only the unauthenticated traffic to solve for with contextual or probabilistic targeting mechanisms.

The Case for Email Addresses

Why have email addresses become such durable connectors in the new era of privacy? It’s simple, really: They are persistent across time and location, structurally unique, and, above all else, an accepted form of digital currency by consumers, advertisers, and publishers; and, unlike cookies and IPs, email can be leveraged to manage consent in a durable way.

The email is as permanent as any kind of digital identifier gets—and as most offline identifiers, for that matter. While an individual can own multiple email addresses and multiple devices, personal emails tend to remain persistent across devices. And email addresses are not tied to a device, unlike a cookie or IDFA, so the consumer must proactively retire that email for it to become unusable.

Previously, advertisers have utilized device graphs that connect smartphones, laptops, tablets, and smart TVs operating on the same IP address, in order to reach an individual or household across devices. But even IP addresses are facing the same headwinds as cookies because they are often used without consent. Email addresses connect the advertiser directly to the person, regardless of what device they’re using. Eventually, the devices owned by an individual can be connected, if the same email address is used to log in from various devices.

Email addresses tie to both online and offline identities. Email, of course, is an online activity, but users often give their email address during offline activities, like signing up for a home delivery after making an in-store purchase. Serving as a definitive anchor to a deterministic set of data, email is highly accurate as compared to the probabilistic and often inaccurate data matching associated with third-party cookies.

Email addresses also benefit from the fact that they can serve as a permanent connector to consent parameters. If a consumer decides she wants to allow one use of her data in one capacity but not another, her preferences can be tracked across sites, apps, and devices if they are tied to her email address. Cookies, whether first- or third-party, can be opted out of, or can expire, as can other forms of temporary consent management.

A New Set of Parameters

But email addresses as identifiers, of course, create a new set of parameters that marketers must navigate.

First, authentication must occur at some point to match a user to an advertiser audience. This means that email-address-based identifiers solve for the universe of logged-on users and first-party data acquired by brands, which is rapidly becoming the new centerpiece of marketing.

In addition, while many people have a single, primary email address, some higher-frequency online users have multiple email addresses they rotate. For a given user, a login across sites, apps, or streaming video services could be pegged to different email addresses. This adds to the complexity of managing email-address-based identities.

There must be a clear value exchange between consumers and the brands they interact with, as consumers only consent to providing their emails and personal information knowingly if they perceive they are getting something of value in return. This is the only way email-based identifiers will continue to provide sufficient scale.

Marketers need to ensure consent is a primary requirement for emails in order for email to continue to serve as the persistent, durable identifier in the future. If the industry as a whole doesn’t manage consent/privacy with care, others will chip away at our ability to use these IDs at all. Sign in with Apple—which gives users the ability to use a random email address to sign into these sites—is a great example of this.

But the most important parameter—which savvy marketers recognize as an opportunity – is that the use of email-based identifiers acknowledges the reality of a new world, where first-party data is king and where user consent trumps addressability in some cases.

As vice president of strategy, Todd Schoenherr leads strategy and innovation at Infutor. Prior to joining Infutor, he held product management leadership roles at mParticle and Signal in the MarTech/AdTech industry, and also worked at Orbitz and Accenture.