tracking
UTM Parameters
Tags appended to URLs that tell Google Analytics exactly where each visitor came from.
What is UTM Parameters?
UTM parameters are tracking tags appended to a URL that pass information about a visitor's traffic source to Google Analytics — identifying the campaign, medium, and source that generated each visit so affiliates can see which promotional activities drive traffic to their content.
Importance of UTM Parameters
UTM parameters are the bridge between your site analytics and your affiliate network dashboard. Without them, Google Analytics shows you that an article received 800 visitors last month but cannot tell you how many arrived from your email newsletter, from your Twitter promotion, from an internal link on another article, or from an external backlink. With UTM parameters on every link you distribute, each traffic stream is labelled and trackable separately — turning GA4 from a traffic counter into a campaign performance tool.
UTM Parameters In Practice
UTM parameters work by appending key-value pairs to a URL using five standard parameters: utm_source (where the traffic originates — 'newsletter', 'twitter', 'youtube'), utm_medium (the marketing channel — 'email', 'social', 'cpc', 'referral'), utm_campaign (the specific campaign name — 'moosend-promotion-april', 'weekly-digest'), utm_content (used to distinguish between different links in the same campaign — 'cta-button', 'header-link', 'comparison-table'), and utm_term (used for paid search keywords). For affiliate marketers, the most useful combination is utm_source and utm_medium on links shared outside your site — in emails, social posts, and external promotions — so GA4 can attribute which off-site activity drove visitors to which content, and that data can be cross-referenced with affiliate commission data from the same period. UTM parameters track traffic to your site; Sub-IDs track conversions from your site to the merchant. Both are necessary for a complete attribution picture.
UTM Parameters Best Practices
- →Use UTM parameters on every link you distribute outside your own site — email newsletters, social posts, YouTube video descriptions, podcast show notes — so every traffic stream is labelled and separately attributable in GA4.
- →Maintain a consistent naming convention across all UTM parameters — 'email' and 'Email' and 'e-mail' appear as three different sources in GA4; lowercase, hyphenated names applied consistently produce clean, usable data.
- →Use utm_content to distinguish between different link placements in the same email or social post — 'header-link', 'cta-button', 'comparison-table' reveals which placement in your email drives the most clicks to your content.
- →Cross-reference UTM-sourced traffic data with affiliate network commission data from the same period — if an email campaign drove 400 visitors and generated 12 commissions, that is a 3% commission rate from email traffic on that content piece.
- →Do not use UTM parameters on internal links within your own site — UTM parameters override the session source in GA4, which means internal UTM links incorrectly attribute page views to the UTM source rather than the original traffic source.
Example of UTM Parameters
An affiliate sends a weekly email newsletter promoting their GreenGeeks hosting review. The link in the email is: affiliateden.com/greengeeks-review?utm_source=newsletter&utm_medium=email&utm_campaign=april-hosting&utm_content=main-cta. In GA4, this appears under Traffic Acquisition as a separate row from organic search visitors to the same page. When they share the same article in a Twitter post, they use utm_source=twitter&utm_medium=social. After two weeks, GA4 shows: email traffic generated 280 sessions from 340 link clicks (82% session rate); Twitter generated 95 sessions from 180 link clicks. Cross-referencing with the GreenGeeks affiliate dashboard, the email-driven sessions produced 9 affiliate commissions; the Twitter sessions produced 1. That data — invisible without UTM tags — tells the affiliate that email is 9x more conversion-efficient than Twitter for this specific content piece.
Related Tools & Services
- GreenGeeks Affiliate Program — Example program used to illustrate UTM parameter traffic attribution and commission cross-referencing
Frequently Asked Questions
What are UTM parameters in affiliate marketing?
UTM parameters are tags added to the end of a URL that tell Google Analytics where a visitor came from. They use five standard fields: utm_source (the origin, like 'newsletter' or 'twitter'), utm_medium (the channel, like 'email' or 'social'), utm_campaign (the specific campaign name), utm_content (the specific link placement), and utm_term (for paid search keywords). For affiliate marketers, UTM parameters label every off-site link — emails, social posts, external promotions — so GA4 can show you exactly which activities drove traffic to which content.
What is the difference between UTM parameters and Sub-IDs?
UTM parameters track traffic to your site, visible in Google Analytics. Sub-IDs track conversions from your affiliate links to the merchant, visible in your affiliate network dashboard. UTM tags on the link to your review article tell you how many visitors arrived from your email newsletter. Sub-IDs on the affiliate link within that article tell you how many of those visitors converted into commissions at the merchant. Both are needed for the complete attribution chain: UTM shows you traffic sources; Sub-IDs show you which content pieces generated the actual commissions.
Should I use UTM parameters on internal links?
No. UTM parameters on internal links — links from one page on your site to another — override the original session source in GA4, incorrectly attributing the page view to the UTM source rather than where the visitor originally came from. For example, if a visitor arrives from Google organic search and then clicks an internal link with utm_source=internal, GA4 will count that second page view as a new 'internal' session rather than continuing the organic search session. Use UTM parameters only on links you distribute outside your own site.