What is utm_medium=email?

Who adds it

Email tools add it by default: Kit sets utm_medium=email, Klaviyo defaults the medium to the message type (email, SMS and so on), and beehiiv uses email for newsletter readers. Marketers also set it by hand.

What it means

Someone clicked a link in an email. Webmail and mail apps often pass no referrer or only a webmail host, so this tag is often the only record of the email source.

What to do with it

GA4 files it under the Email channel. The spellings e-mail, e_mail and e mail also match the rule, but pick one for your own links.

How Vireo shows it

Vireo Pro's UTM campaigns card lists tagged visits by Source, Medium and Campaign, with visitors and pageviews. The tags are read from the first page of each visit, and the same tags feed revenue by source.

In the free plugin, Vireo drops the query string from page addresses, keeping only a few WordPress ones such as p and page_id, so a tagged URL counts as the same page as the untagged one. The visit is counted under the referrer it arrived with.

UTM campaigns are part of Vireo Pro. See UTM campaigns in the docs.

Sources

Email Source = email|e-mail|e_mail|e mail OR Medium = email|e-mail|e_mail|e mail

Default channel group - Analytics Help

They will always be set as utm_source=kit and utm_medium=email unless manually overridden

Automatic UTM parameters - Kit Help Center

the default values of utm_medium have changed from campaign and flow to Message type which includes email, SMS , WhatsApp and push.

Understanding UTM tracking in Klaviyo - Klaviyo Help Center