A tag is simply a word or phrase that is used to describe one or more themes within your content. It is a way of cataloging actual or conceptual references within your text, so that your content can be easily retrieved in the future.
To use an analogy, tags are designed to work similarly to the index of a book. Tags, like the book index, allow you to find content related to specific terms. The only difference is that with tags, you don't need to know which page the content is on.
Tag Updates:
Because of the sheer volume of tags used throughout the site, we have opted to move the bulk of tag processing offline, rather than filtering live. As such, tags are not immediately available to users once they've been added to content. However, testing showed that processing tags offline allowed for a dramatic increase in site performance. When we stacked the pros and cons, performance came out on top. Not to worry, however, because tags are automatically updated within the system every hour, on the hour. So you never have to wait long after you add tags to see them.
The Tags Module:
Tags within the Tags module are automatically refreshed each time the main record list reloads. If you click on a particular member's username under the Members module, the tags, archives and styles for that individual are automatically loaded. Likewise when you deselect the member's username the Tags and Archives sections will reload to reflect the changes. If you select a group under the Groups module, a compilation of all the tags used by members within that group is loaded into the Tags module. If neither member nor group are selected, the Tags module will load up a small collection of popular tags used by everyone on the site. For larger tag collections, the less popular tags are removed by default. To view the entire collection in this instance, click on the "more" link at the bottom of the Tags module.
Search using tags:
You can locate content easily using tags in several different ways. Clicking on an individual tag within the "Keywords" section of a post will retrieve content that matches that tag against the tagged items in the database, or you can use the search function which matches your search term against the title, content and tag fields of items in the database.
Adding your own tags to content:
One or more tags can be added to just about any item that uses an editor window to modify its content. If you see a "Tag this..." field in the editor window, you can add/modify tags for that item. Choosing the tags is completely up to the user. You can select tags which fit the overall concept of your post, or you can simply add custom tags that make it easier for you yourself to retrieve the content at a later date. It's completely up to you.
Allowing others to tag your items:
Keep in mind that if you give permission to other members to tag (reference), comment (respond) or modify (revise) your content, they will have the ability to add tags to your content. Additionally, any tags added to comments in response to one of your posts, will automatically be appended to the tags for your post. This is done to assist in retrieving the posts and related comments at a later date. If you, as the author of a post, do not agree with the tags others have added, you can simply remove the individual tags using the editor.
Lastly, the ability to tag, among other options, is a privilege that only you can grant to others. Always double check your group permissions for each item (under the "Share this..." section of the editor), to ensure they are set correctly.