Tags are like keywords or category labels. Tags help you find content, events, and members which have something in common or similar interests. Tags can be added to groups, your profile, resources, wiki pages, and events.
When creating or editing content, your profile, groups, etc. you can add or remove tags as you wish. If a tag doesn't already exist, simply typing it in a "Tags" form field will create it and make it available for everyone to use.
Using more than one tag will perform an "AND" operation. For example, if you enter "circuits" and "devices", it will find all content tagged with both tags.