Your email address has become a digital breadcrumb for companies to link your activity across sites.
When you browse the web, an increasing number of sites and apps ask for a piece of basic information that you probably hand over without hesitation: your email address. It may seem harmless, but when you enter your email, you’re sharing a lot more than just that.
Why Companies Want Your Email
Advertisers, web publishers, and app makers value your email not just for contacting you. It acts as a digital breadcrumb to link your activity across sites and apps and serve you relevant ads.
For decades, the digital advertising industry relied on invisible trackers planted inside websites and apps to follow our activities and serve targeted ads. Sweeping changes in recent years: Apple’s 2021 feature letting iPhone users block app tracking, Google’s decision to prevent websites from using cookies in Chrome. That forced advertisers to find other ways to track people. Asking for an email address is one simple method.
Imagine if an employee of a brick-and-mortar store asked for your name before you entered. An email address can be even more revealing because it links to other data: where you went to school, the car you drive, your ethnicity.
“I can take your email address and find data you may not have even realized you’ve given to a brand,” said Michael Priem, chief executive of Modern Impact, an advertising firm in Minneapolis. “The amount of data that is out there on us as consumers is literally shocking.”
How Email Tracking Works
Your email address has become a potent piece of data. For many years, the digital ad industry compiled a profile on you based on the sites you visit. Information used to be collected covertly via cookies and invisible trackers. Now that more companies block those methods, new ad targeting techniques have emerged.
Unified ID 2.0 (UID 2.0)
One technology gaining traction is Unified ID 2.0, developed by the Trade Desk. When you share your email on a site using UID 2.0, it transforms your email into a token: a string of digits and characters. That token travels with your email when you use it to log in to other apps and sites using UID 2.0. Advertisers can link accounts together based on the token and target you across platforms.
Since your email isn’t revealed to the advertiser, UID 2.0 may be seen as a step up from cookie-based tracking. However, Mozilla called UID 2.0 a “regression in privacy” because it enables the type of tracking behavior modern browsers were designed to prevent.
Simpler Tracking Methods
An email could contain your first and last name, and data brokers have already compiled comprehensive profiles on your interests. A website can upload your email into an ad broker’s database to match your identity with a profile containing enough insights to serve targeted ads.
What to Do
1. Create Multiple Email Addresses
Use unique addresses for different purposes:
movies@yourdomain.comfor streaming servicesshopping@yourdomain.comfor retailersfitness@yourdomain.comfor health apps
This makes it hard for ad tech companies to compile a unified profile. If you receive spam to a specific account, you’ll know which company shared your data.
Downside: Time-consuming to manage multiple accounts and passwords.
2. Use Email-Masking Tools
Apple Hide My Email (iCloud+ subscription, $0.99/month):
- Creates aliases that forward to your real email
- Works best within Apple ecosystem
Mozilla Firefox Relay:
- 5 free email aliases
- $0.99/month for unlimited aliases
- Cross-platform
3. Opt Out of UID 2.0
For sites using UID 2.0, opt out at transparentadvertising.org. Not all sites use UID 2.0, but it’s a start.
4. Do Nothing (If You’re Okay With It)
If you enjoy relevant advertising and have no privacy concerns, accept that sharing some information is part of the transaction for free content.
My Approach
I juggle four email accounts devoted to main interests: food, travel, fitness, and movies. I use the movie-related email for ticket sites and streaming services. Those apps know my movie preferences but not everything about me.
Source: Adapted from NYTimes