You will be able to set naming rules for UTM values so reports group traffic the way you expect.
A month after Farah started tagging her links, she opened the traffic acquisition report and found her newsletter in four places. One row said source "Newsletter", another "newsletter", a third "email-newsletter", and the fourth "nl". She had tagged some links herself, her part-time assistant had tagged others, and the email tool had added its own. The campaign worked, but the report made it look like four small campaigns, none of them impressive.
Tags only help if everyone writes them the same way. This lesson is about the rules that make that happen.
UTM values are case-sensitive in GA4. "Email" and "email" are two different mediums, and "Instagram" and "instagram" are two different sources. GA4 will not merge them for you, and they cannot be merged after the fact in the standard reports. Every visit is filed under exactly what was typed.
Spaces cause their own trouble. A space in a link gets converted to "%20" or a plus sign, depending on where the link was built, so "work trousers" can arrive as two different values as well. Punctuation and special characters behave unpredictably in some apps.
The fix is boring and it works: lowercase everything, use hyphens instead of spaces, and allow only values from a fixed list.
Write down every source and medium your business is allowed to use, and treat anything else as a mistake. For Farah, the list is short.
Sources: newsletter, instagram, facebook, tiktok, whatsapp, bazaar, partner-name for any partner site, and google or meta for paid ads where they are not tagged automatically.
Mediums: email, social, paid-social, cpc, referral, and one value for print and QR codes, which she chose to call qr.
When a new channel comes along, say a podcast sponsorship, the person adding it updates the list first and then tags the link. That one rule prevents most of the mess.
GA4 sorts visits into default channel groups such as Email, Organic Social, Paid Social, Paid Search, Referral and Direct. It decides mainly from the source and medium on each visit, following rules Google publishes in its GA4 help centre. A visit with medium "email" lands in Email. A visit with medium "social" usually lands in Organic Social. A visit with medium "cpc" from a search engine source lands in Paid Search.
If you invent a medium the rules do not recognise, such as "newsletter-blast" or "ig-story", GA4 cannot place it, and the visit goes to a group called Unassigned. Your channel report then shows a growing Unassigned row and a mysteriously small Email row, even though the email did its job.
So before you add a medium to your list, open Google's published definitions of the default channel groups and check where it would land. Use the standard words where one fits. For a channel with no standard home, like Farah's printed QR codes, decide on purpose: either accept that those visits sit in Unassigned and filter for them by source, or set up a custom channel group in GA4's admin settings that gives them a home. What you want to avoid is landing there by accident.
The definitions change from time to time, so check them each time you add a medium rather than relying on a list from memory, this one included.
utm_campaign has the most freedom, which is why it gets messy fastest. Pick a pattern and stick to it. A good pattern starts with the date, because reports sort alphabetically and a date at the front puts campaigns in time order.
Farah uses year, month, then a short theme, all lowercase with hyphens:
2026-11-work-trousers 2026-12-year-end-sale 2027-03-raya-edit
Anyone in the team can tell when each ran and what it was about. A name like "promo" or "sale2" tells you nothing next year, and "Raya Sale FINAL v2" breaks three rules at once.
For utm_content, a simple description of the placement is enough: header-image, button, bio-link, story-1. Keep these lowercase too.
The rules only work if the people tagging links can see them while they do it. One page is enough. Farah's has four parts: the allowed sources, the allowed mediums with a note on which channel group each lands in, the campaign name pattern with two examples, and three finished links built correctly. She pinned it at the top of the shared folder and sent it to her assistant and the freelancer who runs her ads.
Lesson 2.4, Build your UTM tagging sheet, turns these rules into dropdowns so nobody has to remember them. For now, the page is the important part, since a tagging sheet built without agreed rules just produces mistakes faster. Write the page for your own business, using your real channels, with a few example links that show the rules in action.
Write your UTM rules on one page: allowed sources, allowed mediums, a campaign name pattern and three example links.
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