Tag sequencing was introdced to Google Tag Manager in late 2015. Its main purpose was to facilitate the sequential firing of tags that have dependencies with each other. Due to the asynchronous nature of third-party libraries like Google Tag Manager, it's difficult to establish an order of completion with tags that compete for their chance to fire. Tag sequencing changed this, as it allows you to establish setup and cleanup tags - the former firing before the main tag, and the latter after.
A while ago I posted a #GTMTips post where I detailed the steps you can take to opt-out of all Google Analytics tracking and the DoubleClick redirects that often follow. It was a fun exercise, but because it relies on preventing requests on a tag-by-tag basis (using the ubiquituous customTask), it can be a chore to handle in large containers. In this article, we'll continue with the theme of opting out from Google Analytics tracking by leveraging a solution provided by the tool itself.
A recent update to Google Tag Manager introduced a feature which has been on the wishlist of many users for a long time. It's called Tag sequencing, and its purpose is to facilitate the sequential firing of Tags. The idea is that you can specify a setup and a cleanup for each Tag in your container. This article is intended to function as a quick tour of the feature.