What is "Not Set" and why do I keep seeing it?

Seeing "Not Set" as a referral for your downloads means Chartable was not able to determine where the user came from. 

Not Set usually appears when the user came from a mobile app, a HTTPS link, or their browser has a Do Not Track signal emitting. Here's an article breaking it down. 

To avoid "Not Set" from appearing, we recommend using Source IDs for your SmartLinks.