In technical terms, a tag is a piece of metadata assigned to a content node (usually a page) within CQ5 WCM. You can also think of them as keywords or labels that you attach to page to help you find it again.

Within CQ, tags can be grouped into various namespaces. Such hierarchies allow taxonomies to be built. These taxonomies are transparent across CQ WCM, CQ DAM and CQ Social Collaboration.

There are no restrictions on the tags you can create - though they must be unique within a specific namespace.

Tags can be created by either the page creator, or viewer. Irrespective of their creator, all forms of tags are made available for selection, both when assigning to a page, or when searching.

As with pages you can perform the following on tags and namespaces:

Tags are used by the teaser component, which monitors a user's tag cloud to provide targeted content.

A major strength of tags is their flexibility. No structure is needed (though namespaces do allow a minimal hierarchy). You can also assign them spontaneously, then search for them as required.

However, the flexibility can prove to be a disadvantage. It is all too easy to end up with many similar tags relating to basically the same thing; page and pages, impersonator and impersonators are two simple examples. For this reason, CQ allows you to see existing tags before you create a new one, and to group tags into namespaces.