utmmedium

utm_medium is a URL parameter used in campaign tagging to indicate the general category of the marketing medium through which a user arrives at a website. It is part of the UTM (Urchin Tracking Module) set that analytics tools rely on to attribute traffic and measure campaign performance. Together with utm_source (the referrer or publisher) and utm_campaign (the specific campaign name), utm_medium helps classify visits in reports.

In practice, a tagged link might look like: https://example.com/?utm_source=newsletter&utm_medium=email&utm_campaign=summer_promo. Another example is utm_source=google&utm_medium=cpc&utm_campaign=search_sales, used for paid search traffic. The medium value should reflect the broad channel or method, such as email, cpc, social, banner, affiliate, or referral.

Common values include email, cpc (cost-per-click), social, display, banner, affiliate, and referral, among others. It is important to use consistent, descriptive values and avoid spaces by using delimiters like hyphens or underscores. Best practices include keeping all utm values lowercase, avoiding personally identifiable information, and using a centralized tagging guide to maintain consistency across campaigns. URL builders or tag-management tools can help generate properly encoded links and prevent errors.

Limitations include reliance on the analytics platform to interpret UTMs, potential misattribution if tags are inconsistent, and the possibility that shared or modified links can lose or alter utm_medium data. UTMs do not track beyond the tagged session and cannot replace server-side attribution.