As explained in the “What is Traffic Source?” FAQ, if there is not a custom Traffic Source rule for the given referring URL, then the Traffic Source will be set to the domain name of the referring URL. For example, let’s say your website is Sports.com. A user can navigate to your website by clicking on a link to it from the “https://bluetriangle.com/industry-benchmarks/banking/” URL. The Sports.com page would then have a document.referer of https://www.bluetriangle.com/industry-benchmarks/banking/. The Blue Triangle tag does not have a custom Traffic Source rule for a referring URL of https://www.bluetriangle.com/industry-benchmarks/banking/, so in this case the Traffic Source would get set to the base domain of bluetriangle.com.
However, the Traffic Source could get set to Sports.com if the user instead starts their session on a page of the Sports.com website that is not loading btt.js and then navigates to another page of the Sports.com website that is loading btt.js. This can also happen if the Sports.com website has a GDPR or CCPA landing page that does not load btt.js until after a user accepts the cookie policy, or in cases where only certain parts of your website are loading btt.js. These are two common scenarios, but is not a comprehensive list of all the ways that the Traffic Source could get set to Sports.com.