Reality: People have multiple email addresses. If you use email as a primary identifier, you’ll have a fragmented view of each person, resulting in repetitive messaging and unreliable attribution.
 
Now what? Your identity approach should unify each person’s multiple email addresses into one profile for more efficient, personalized media delivery and accurate measurement. 

Reality: Devices in the same household typically have the same IP address, making it difficult to reach the right person and tailor their messages efficiently. And because 50% of household IP addresses are reassigned monthly, relying on them for a long-term connection is nearly impossible.
 
Now what? You should match individual people—not households—to their devices based on a holistic view of each of them, including email address and purchase data. These tend to be more accurate and stable over time.

Reality: One-third of cookies are seen for only a single day, because companies like Apple refresh them every 24 hours. And each person is typically associated with multiple cookies at any given time.
 
Now what? When you consolidate all the cookies assigned to a person into a single profile, you’ll get a complete view of them. That way, you won’t lose your connections every time a cookie gets deleted.

Reality: Social media companies are walled gardens—they don’t share IDs outside of their platform. And because they aren’t transparent with their data, you can’t get a holistic view of your customers and prospects across all of their channels and touchpoints.
 
Now what? Unless you want to rely solely on social media companies to serve your advertising, social media ID isn’t an ideal way to achieve people-based marketing at scale.