Traffic Source and Referrer are two names for the same parameter in the Blue Triangle portal (it may also be referred to as the “campaign source” in some parts of the API documentation). This field groups the kind of traffic that visits a site based on a particular source, such as search engine, other website, or a direct navigation. You do not need to do anything to set the Traffic Source, as it will be collected automatically.
The Traffic Source field is typically set to the domain name (or service name) of the referring URL. The referring URL is collected through document.referrer. Blue Triangle has some additional logic to modify the Traffic Source to the service name in certain cases, such as changing https://www.google.com to just “Google”. If there is not a custom rule to for that service name, then the Traffic Source will be set to the base domain (similar to location.hostname). Subdomains and protocols are typically left off of the Traffic Source field, so that field would display “google.com” instead of https://www.google.com.
It is also worth noting that the Traffic Source is set at the session level, since that user will be referred to the customer’s website once at the start of the session (like if someone Google’s “Blue Triangle” and then clicks on the Blue Triangle website link).