The digital ad industry has spent a great deal of time over this past year pondering a big question that is crucial to how it operates: How exactly do we replace cookies?

One answer that has gained considerable traction is the use of anonymized email addresses to create cookie-like identifiers.

There’s no question that email data plays a key role in marketing. It’s invaluable for sending existing customers promotions, for example, and first-party email lists are the backbone of many companies’ customer-retention efforts. Yet the strategy of going all-in on a single email-based ID to support the digital ad economy faces some challenges that should give CMOs pause.

Challenges with Using Only Email-Based IDs for Digital Advertising

1. Using email identifiers just like cookies ignores privacy concerns

Think for a minute about how we got here. Consumers have become far more aware of and vocal about how their data is being used online. On a base level, most don’t like the feeling of being followed around the web with invasive ads.

Moreover, the population at large has become more wary of sharing information via digital channels because they fear it will be misused (or simply used in ways they don’t know about or can’t control). That reality is at the crux of the many regulations that have been enacted over the past few years, with stricter rules likely on the horizon.

So why would we simply swap out cookies for hashed email addresses, and keep operating solely in the same manner? Targeting solutions built only on email-identifiers feels like a vote for the status quo, which doesn’t appear to be what the world wants right now.

2. Relying solely on email identifiers ignores device sharing

One of the bigger challenges with cookies, even before the more recent backlash, is that they don’t allow for easy cross-device tracking. Cookies are really a desktop, browser-centric device in a world that is increasingly mobile and smart TV-driven.

Emails face a similar challenge. It’s difficult for a marketer to know whether mom or the kids are using a phone at any given moment, for example, if only mom’s email address is associated with that device.

3. Emails can miss the mark on connected TV

Accounting for device sharing is an even bigger challenge for devices that are designed to be used by multiple people at once: e.g., smart TVs. Ad-supported streaming is one of the fastest growing and exciting sectors in media, which means that marketers increasingly need ways to discern who is in front of this screen at a given moment, and who is watching together.

Email-based identifiers struggle in this world (since they are, by nature, tied to one person). This is yet another reason why household-driven targeting is increasingly so attractive. (To learn more about Adelphic’s approach to household targeting, learn more about the Viant Household ID.)

4. Email identifiers face a looming attribution gap

The more that brands look to gauge the business impact of every ad dollar they spend, the more they are pushing for comprehensive, data-driven attribution. Unfortunately, email identifiers face an inherent problem here, since ad exposures often occur on one more device, and conversions take place on another.

Thus, it will be difficult to connect an ad delivered via CTV through a specific app (which is often associated with a specific member of the household’s email address) with a purchase that occurs on a mobile device that is being used by another member of the household. This approach extends the challenge of multi-touch attribution instead of simplifying it.

5. Cookies were never that great to begin with

So why rely on emails the same way when the industry should be constantly adapting and innovating?

As mentioned, even before tech companies large and small began pushing to phase cookies out, they were becoming less and less effective for brands (mobile operating systems often don’t support them, some consumers regularly delete them, etc).

So in this time of AI and machine learning, why are we looking to replicate these same tactics, instead of looking for more innovative and engaging ways to target consumers? Marketers deserve a better option.

If not email addresses, then what?

Adelphic employs a household approach to targeting and measurement, which as mentioned above is a better option especially when it comes to channels like CTV. While not an identifier, the Viant Household ID is fully integrated within Adelphic, and has allowed users to pull the plug on cookies while driving stronger performance with a household-based approach.

To learn more about the Viant Household ID, as well as the identifiers that are currently in the bid stream, explore Viant’s interactive bid stream analysis dashboard.