UTM parameters

There are five classic tags: utm_source (who sent the visit, such as google or newsletter), utm_medium (the channel, such as cpc, email or social), utm_campaign (the campaign name), and the optional utm_term and utm_content for keywords and ad variants. Analytics tools read them from the landing page's address and credit the visit, and any later conversion, to that campaign. The name comes from Urchin, the analytics company Google bought and turned into Google Analytics.

Consistent naming matters: GA4 treats Email and email as different sources, so teams keep a shared naming sheet or a link builder. Tagging internal links on your own site is a mistake, because it overwrites where the visitor originally came from. Ad platforms add their own click ids automatically (gclid for Google Ads, fbclid for Meta), and canonical tags stop tagged URLs from showing up as duplicate pages in search.