A 'Tag Management System' (TMS) is a tool used in digital marketing and web analytics to manage the deployment, updating, and testing of tags on a website. It allows marketers to add, edit, and disable tags without needing to modify the code directly on the website.

Using a TMS simplifies and streamlines the process of tag management, reducing the reliance on IT resources and minimizing the risk of errors. It provides a centralized platform for managing various tags, enhancing efficiency and agility in marketing and analytics efforts.

TMS solutions are crucial for handling the complexity and volume of modern web analytics. They enable marketers to quickly adapt to changing marketing strategies and user behaviors, ensuring that the data collected is accurate and relevant to current needs.