If the email address is the unique identifier, then how are duplicate email addresses made?
In our database, we have some people whose entire information including email are the same. The only thing that differs is "Updated" and "Id." The only ways for this information (in our case) to be imported are through lists, and form fills. And I read on a thread in this community that Marketo only dedupes when the email is entered directly into it from Lists, API, or Form Fills. So just wondering why/how this is happening?