What do UTM parameters do?

When utm parameters are added to the destination of a referral or ad link, the click sends those values to Analytics as well. In the Traffic acquisition report they show as Session source, Session medium, Session source / medium and Session campaign. Parameters can be written in any order. A question mark separates them from the address, each pair is joined with an equals sign, and the pairs are separated with an ampersand.

If a parameter is being added, utm_source, utm_medium and utm_campaign are used together. The help page specifically asks that, once one parameter is set, the relevant others be set too. utm_id and utm_source_platform are on that list. A value left out stands in the report as (not set).

Not every parameter fills a dimension. utm_creative_format and utm_marketing_tactic are not currently reported in Google Analytics properties. The others go to source, medium, campaign, id, keyword, content and platform rows.

The same values are not written into the Landing page + query string or Page path + query string dimensions. A campaign name looked for in those two will not be there. The value sits on the Page location dimension. The row itself is read in the Traffic acquisition report. How the columns split into users, sessions and key events is in the piece on the reports.

Parameter values are case sensitive. utm_source=google and utm_source=Google are two source rows. SpringSale and Spring_Sale are two campaigns. Meta and meta are two values. The help page recommends one source value per platform, one medium value per channel, and the same spelling every time. It treats lowercase as part of that habit. This is not a template N2 imposes. It is the recommendation on that page. If the same work travels under two spellings, the report splits into two rows.

The default channel group is a rule Google maintains, applied after that row. It cannot be edited. The rules look at source and medium together, and they are not case sensitive. Meta and meta can therefore stand as two source rows and still fall into one channel. An arrival that matches no rule becomes Unassigned. For manual traffic, the Email channel matches when the medium is email, e-mail, e_mail or e mail. The source can be one of those spellings too. Where any other medium lands depends on whether the source is also in the rule.

The URL builder page gives paid_social and organic_search as examples of medium values kept distinct from each other. Those examples are a naming recommendation. They are not the same list as the channel-group rules. organic_search is not the same spelling as organic in the Organic Search rule. If the medium does not match the spelling the rule looks for, and the source is not on the list either, the row can stay Unassigned. That a channel in the report is an arrival rule is covered in the piece on channels. Which question in the plan a campaign name belongs to sits in the strategy piece.

On linked products such as Google Ads, Campaign Manager 360, Display & Video 360 and Search Ads 360, auto-tagging fills more dimensions than a UTM typed by hand. It adds a GCLID to a Google Ads address. Campaign, ad group, keyword and query arrive that way. A manual tag does not take the place of those dimensions.

When auto-tagging and a manual tag are together, Analytics uses the auto-tagged values for source, medium and the other traffic-classification dimensions. utm_content and utm_term can still be added by hand. They go to the Manual ad content and Manual term dimensions.

When a GCLID or DCLID cannot be used as intended and any UTM is on the address, every cross-channel traffic-source dimension is built from the UTM alone. A missing parameter becomes (not set). Putting a partial utm_source on a Google Ads link can move the row somewhere other than google / cpc. This article does not describe stripping the tags off an account. The reading is this: while auto-tagging is in place, every parameter added by hand can become the source itself, gaps included.

If the User acquisition report shows only Direct, the help page points to linking ad accounts or tagging destination addresses. Direct is a person who arrives by typing the address. The same bucket also covers a link that was copied and pasted, a bookmark, some social arrivals, an address in an offline document, and a move from an HTTPS page to an HTTP page. A tag names only the click that carried it.

A session that starts as a direct entrance can be written to the UTM values already known for that user. How to read that sits in the piece on the reports. In a digital marketing plan the parameter is not there to impose a separate template on every channel. It is there so that, at month end, the click can be found on the row of the work it belonged to.