UTM parameters are pieces added to the end of a link that analytics reads as campaign information. They are the reason a report can tell you that eleven people came from your newsletter rather than simply that eleven people arrived. Without them, most of your own marketing arrives anonymous.
Briefly explained
- Tags written into the link itself, read by analytics.
- Five exist. Three do the work.
- Untagged campaign links end up filed as direct traffic.
- A naming convention matters more than the tags do.
What are the five tags?
- utm_source: Where the click came from.
newsletter,yard_sign,supplier_site. - utm_medium: The type of channel.
email,sms,print,social. - utm_campaign: The specific push.
spring_promo_2026. - utm_term: Optional. Usually a keyword.
- utm_content: Optional. Which version of the link, for testing.
Source, medium and campaign carry almost all the value. The other two are for cases where you genuinely compare two variants.
What should you tag, and what should you leave alone?
Tag everything that Google does not tag for you.
- Tag: email, SMS, QR codes, partner and supplier links, print, anything you place on someone else’s site
- Do not tag: Google Ads, where auto-tagging does it better
- Never tag: links between pages of your own site, which overwrite the original source and split the visit in two
Why does untagged traffic matter?
Because it disappears into direct traffic, the bucket where attribution goes to die.
The estimate link your office texts, the QR code on a leave-behind, the seasonal email, the link a supplier added to their dealer page — all of it arrives looking like somebody typed your address from memory. The campaign gets judged on nothing.
How do you keep it usable?
The convention is the whole job. The tags are trivial.
- Lowercase everything. Always.
- Underscores instead of spaces.
- A fixed, short list of allowed mediums. Write it down.
- Store the built links somewhere shared, so nobody invents a new spelling.
- Check quarterly that the values in your reports still match the convention.
UTM data degrades the moment two people start guessing, and it degrades invisibly, because every misspelling still produces a row in the report.
What do the terms mean?
- Auto-tagging: Google Ads adding its own parameter, which is why you do not add UTMs there.
- Source / medium: The pair most reports group by.
- Referrer: Where the browser says the visit came from, when it says anything at all.
- Direct: Where analytics files anything whose origin it could not work out, untagged links included.
Owner questions
