What is the difference between the Net New, Hydrated and All profiles lists?

The Net New email list contains profiles that we were able to identify traffic for, that was not in your email list previously.

The Hydrated email list contains existing profiles that Audiences was able to provide more personal information about. For example, if you had a profile where only the email was known, and Instant was able to provide their first + last name, then they would be added to the Hydrated list.

Profile Hydration enables more opportunities for personalised messaging (in the case that names are provided). Fields will only updated if they were previously empty.