Key takeaways

In this module, you learned:

• "Original referring domain" captures the very first domain that sent a visitor — not the most recent. Unlike the standard referring domain dimension (which reflects the last referral), the original referring domain is sticky across all subsequent visits. This makes it useful for understanding the very first source of acquisition, separate from any later re-engagement.
• Campaign tracking codes tie traffic and conversions to specific marketing efforts. A tracking code is a unique identifier appended to a campaign URL and captured in the `s.campaign` variable. It lets you attribute downstream conversions — orders, leads, signups — back to the specific ad, email, or promotion that drove the visit, with configurable first-touch, last-touch, or linear attribution.
• Marketing channels persist across visits; traffic sources reset at each new visit. By default, marketing channels have a 30-day expiration, meaning a visitor who returns within 30 days can still be attributed to the channel that originally brought them. Traffic sources, on the other hand, expire at the visit level — each new visit overwrites the previous value with the most recent referrer.
• Classifications map human-readable labels onto raw captured values without changing what was collected. A campaign code like "A1234-SPR-PROMO" might be the actual value in the data, but a classification lets you display it as "Spring Email Promotion" in reports. This keeps implementation clean while making reports interpretable for stakeholders who don't know the underlying codes.
• Campaign reporting and marketing channel reports serve different analytical purposes. Campaign tracking codes are best for measuring specific paid marketing efforts with precise attribution control. Marketing channels use predefined rule-based classification to categorize all traffic — paid, organic, direct, and more — into broader buckets, making them more suitable for high-level channel mix analysis.