Track information other than just email
Besides just tracking the email address, there should be an option that the survey website can hold name, email and account names or companies. NPS is about contacting customers based on their responses and knowing exactly who it's coming from will help with follow ups.
We building in some super cool functionality that will allow you to add in additional fields for email sends that will be linked to the email address in the reporting section.
Will keep you updated :)