What are tags?
Tags allow you to make properties visible in the knowledge graph. Normally, only objects are shown in the knowledge graph but their properties aren't. With tags, you can turn an object's property into a "fake" object of type tag. This newly promoted property will be shown in the knowledge graph, automatically connected to the object it belongs to with a link that says "tags".
You have objects of type alert in SquaredUp. Alerts have different properties like ID, label, and status. You want to show a correlation between the alert and status in the knowledge graph. But correlations can only be shown between objects, and status is a property, not an object. You turn the status property into a "fake" object of type tag, by adding the property as a tag. Now the status property will be shown in the knowledge graph, automatically connected to alert in this way:
status:warning --tags--> alert