What are UTM parameters?

The five parameters

• utm_source. Where the traffic came from — `newsletter`, `linkedin`, a partner's name.
• utm_medium. The type of channel — `email`, `cpc`, `social`, `referral`.
• utm_campaign. The specific initiative the link belongs to.
• utm_term. The keyword, on paid search. Largely vestigial elsewhere.
• utm_content. Which variant or placement, used to separate two links in the same email or two creatives in the same campaign.

Why the name is a fossil

Urchin was a web analytics company Google acquired in 2005; its product became Google Analytics. The parameter prefix survived the rebrand and is now a permanent piece of industry furniture that nobody would design today.

It is worth knowing only because it explains why the parameters are named after a company most people have never heard of.

The conventions that actually matter

UTM reporting degrades through inconsistency rather than through anything technical. Four rules prevent most of it.

Lowercase everything, because most analytics treats case as significant and the split is invisible until you notice traffic halved.

Fix the medium vocabulary. `cpc`, `ppc` and `paid` will fragment one channel into three. Agree the list once and enforce it.

Generate, do not type. A spreadsheet or a small tool that builds links from the agreed taxonomy eliminates the entire class of typo errors.

Do not UTM internal links. Tagging a link between two of your own pages restarts the session and overwrites the original source, destroying the attribution you were trying to measure. This is the single most common UTM mistake.