Open the traffic sources report in almost any store's analytics and you'll find the same thing: "facebook", "Facebook", "fb" and "meta" listed as four different sources. "Email", "newsletter" and "klaviyo" counted separately. A chunk of traffic labelled "unassigned" that nobody can explain.

None of that is the analytics tool's fault. It's what happens when several people tag links in their own style. The fix is a naming convention: a short, written agreement on how every campaign link is tagged.

The five tags

UTM tags are the extra pieces of text added to a link so your analytics knows where a visitor came from. There are five, and you'll use the first three on every link:

  • utm_source: where the link lives, like facebook, instagram or newsletter.
  • utm_medium: the kind of traffic, like email, paid_social or cpc.
  • utm_campaign: the campaign or promotion, like spring_sale_2026.
  • utm_content: optional, which creative or link, like hero_button.
  • utm_term: optional, mostly for paid search keywords.

A tagged link looks like this:

https://example-store.com/products/cleanser
  ?utm_source=instagram
  &utm_medium=paid_social
  &utm_campaign=cleanser_launch_2026
  &utm_content=video_a
A launch planning board with a channels column listing email, paid social, search and influencers.
Cropped to 4:3: every channel on the plan gets its own agreed source and medium.

The convention

1

Lowercase everything

Most analytics tools treat Facebook and facebook as two sources. Lowercase removes the problem completely.

2

Use underscores, never spaces

Spaces turn into %20 in links and make reports hard to read. Pick underscores and use them everywhere.

3

Fix the list of mediums

Agree on a short list, such as email, paid_social, cpc, affiliate, influencer and referral, and use nothing else. Tools like Google Analytics 4 sort traffic into channels partly by reading the medium, so made-up values tend to end up as "unassigned".

4

Name campaigns the same way every time

For example what_when, such as spring_sale_2026. Anyone should be able to guess the campaign name without asking.

5

Keep the list in one shared place

A single spreadsheet with every source, medium and campaign in use. New values get added there first, then used.

Never tag your own site's links

UTM tags are for links that bring people to your site from somewhere else. Tagging a banner on your own homepage starts a new visit with the wrong source, and the original source of that visitor is lost.

Fixing the past

You can't retag old visits, but you can tidy the reports. Most tools let you group messy old values ("fb", "Facebook", "meta") under one clean name in a report. Do that once for the history, then let the convention keep new data clean.

It's a small amount of discipline. In return, every report about where your customers come from becomes something you can actually trust.