Why it matters to a buyer
Without UTM parameters, traffic from a specific email campaign or a specific partner link often gets lumped into generic referral or direct traffic, which makes it impossible to tell which specific channel activity actually drove a result. For a buyer running multiple campaigns at once, inconsistent or missing UTM tagging is a common, avoidable reason a report cannot answer basic questions like which email or which partner link actually produced the traffic and conversions being reported.
How it is measured or applied
UTM parameters are added to any link a business controls, outbound emails, social posts, partner placements, using a consistent naming convention agreed in advance, since inconsistent capitalisation or naming, "Newsletter" versus "newsletter," splits what should be one channel into several in reporting. They should not be added to internal links or organic search results, since Google appends its own tracking and internal UTM tags can corrupt session attribution. Tagged links are checked in GA4's traffic acquisition report, filtered by source, medium and campaign, to confirm traffic is being classified as intended.
Sources
- [GA4] Set up and manage UTM parameters, Google Analytics Help
