UTM tags
/juː tiː ɛm tæɡz/plural noun
UTM tags are URL parameters that identify a link's source, channel and campaign. Web analytics software can use them to attribute visits to that campaign.
We add UTM tags to ad links so we can see visits by campaign.
An ad, a newsletter and a social media post can all link to the same page. UTM tags add information about where each link is used. The visitor reaches the same page, while your web analytics software can distinguish the source.
What does a tag contain?
Common parameters are utm_source for the source, utm_medium for the channel and utm_campaign for the campaign. An ad could use the values google, cpc and custom-software. The utm_content parameter can distinguish individual ads within a campaign. Google describes these parameters in its guide to campaign links.
The tags do not collect data themselves. The website needs software that reads the parameters and includes them in reports. Use consistent names: spelling the same campaign differently can split its results across several rows.