Tagging

Tagging lets you assign metadata to AWS resources in the form of tags. Each tag is a simple label consisting of a customer-defined key and an optional value that can make it easier to manage, search for, and filter resources.

You can use tagging on AWS resources to apply business and organization information to your usage and cost, this provides additional insights to optimization from an organisation perspective.

Tagging AWS resources enables you to create general purpose automation scripts based upon tags rather then individual resources.

Resources

Use Tagging to Organize Your Environment and Drive Accountability
AWS Tagging Strategies