What are a container, a tag and a trigger?
Three words cover the whole tool (Google Tag Manager Help, "Set up and install Tag Manager").
| Word | What it is | An example |
|---|---|---|
| Container | The one piece of code on your website, with an ID starting GTM. Everything else lives inside it | GTM-XXXXXXX on every page of the site |
| Tag | A piece of tracking code the container will run | The Google tag for GA4, the Meta Pixel, a Google Ads conversion tag |
| Trigger | The rule that says when a tag runs | On every page view; when someone reaches the thank-you page; when the Book now button is clicked |
| Variable | A value a tag or trigger can read | The page URL, the order total, the form's name |
A conversion, in these terms, is a tag with a trigger: "send Google Ads a conversion worth the order total when the page is /thank-you". Without Tag Manager the same thing is a line of code a developer pastes onto one page, and the next developer cannot find.
Why does an owner need to know this exists?
Because tracking breaks quietly, and the person who set it up has usually gone. A website redesign drops the container. A new booking system changes the thank-you page URL and the trigger never fires again. Google Ads keeps spending with a conversion tag that reports nothing, and the account looks like it stopped working when only the measurement did.
An owner who knows the words can ask the right question of a developer or an agency: is the Tag Manager container on every page, which tags are in it, and what triggers them. And an owner who owns the Tag Manager account, with the developer as a user, can hand the tracking to the next developer in five minutes.
What does a broken tag cost? (example figures)
A Ballarat accounting firm runs Google Ads at $900 a month for tax-time enquiries. In July the website moves to a new builder. The new site has the Google tag for Analytics, placed by the builder, but the Tag Manager container with the Google Ads conversion tag is left behind.
| June (container on the site) | August (container missing) | |
|---|---|---|
| Spend | $900 | $900 |
| Enquiry forms actually sent | 21 | 23 |
| Conversions Google Ads reported | 21 | 0 |
| What Smart Bidding did | Bid for people likely to enquire | Lost its target and spent on clicks |
| What the owner concluded | Ads are working | Ads stopped working |
The enquiries never stopped. The tag did, and two months of Smart Bidding ran blind. Putting the container back on the new site took the builder twenty minutes once someone knew to ask.
How do you check your own site in two minutes?
Open your website in Chrome and install Google's free Tag Assistant extension, or open the page source and search for GTM. If a container is there, open tagmanager.google.com with the business's Google account and look at the Tags list: each one should have a trigger and a recent firing. If you cannot sign in because the account belongs to someone else, that is the first thing to fix, before any campaign.
What does Cora do with Tag Manager?
Once Google is connected, CoraVision reads the containers in your Tag Manager account, their names and IDs, every night, alongside what it reads from Google Analytics 4 and Google Ads. Together those tell Cora how far your tracking can be trusted, which is what your Trust Score measures: a paid channel with no conversion tag costs points, and fixing it is a step in your action plan. CoraVision reads only; it never adds, changes or removes a tag. When a tag needs adding, Cora shows you, or your developer, where on the screen.
Questions
Do I need Tag Manager if my site is on Shopify or Wix?
Usually not. Shopify, Wix, Squarespace and WordPress plugins such as Site Kit place the Google tag and the Meta Pixel for you through settings. Tag Manager earns its place when you have several tags, a custom website, or a developer who comes and goes.
Is Tag Manager the same as Google Analytics?
No. Analytics is a tag that reports visits. Tag Manager is the box the tag sits in, along with every other tag. You can run Analytics without Tag Manager and Tag Manager without Analytics.
Who should own the Tag Manager account?
You, the business owner, with the developer or agency added as a user. An account owned by a departed contractor is one of the common reasons a site's tracking cannot be changed, and it is cheaper to set up correctly than to recover.