How to collect contact info from new recipients of your send-outs
This will give you a full vision of who opens the send-out once it's delivered and is very valuable when there are multiple decision-makers involved.
If you send the document to a Director of Sales, but she forwards the email to her VP of Sales (using a different IP Address), you will know the VP of Sales' name and email. This helps you begin to map your customers' buying journeys and create best practices to address them.
The great thing about the pop-up is that it will appear as if the original recipient is doing her due diligence and granting security access to the new recipient.
Once they authenticate themselves with a name and email, you will receive their contact information in real-time and know how long they are looking at the send-out.