UTM parameters are tags added to the end of a link — utm_source, utm_medium, utm_campaign, and optionally utm_term and utm_content — that pass campaign information into analytics tools when someone clicks. They are the standard way to label inbound traffic.
Why it matters for agencies
Consistent UTMs are the foundation of reliable attribution: without them, campaign traffic collapses into “direct” or “referral” and you lose the thread between spend and outcome. A shared naming convention is essential — sloppy tags fragment reporting — which is why a UTM builder keeps every link tagged the same way across channels and clients.
Run the numbers with the free UTM builder.