Categories are more permanent and structured than tags. Any content may be marked with multiple categories and/or tags. Tags are more specialized, sometimes transient; they do provide excellent keywords for search of a specific item.

Category descriptions

• Action involves something about which a response is required, including nominations,
  applications, etc.
• Business includes an item of internal business, such as something that will be handled by committee or at a faculty meeting
• Event and conference information that may be of interest to faculty
• Interest will be used to identify content that I may find of personal relevance but deem share-worthy
• News is exactly that, either for or about the department
• Policy will be used to either announce or remind about new and changed policies and procedures
• Reports and minutes will be announced through the blog using this tag (although often link to a file requiring authorization)
• Undergraduate student-related
• Graduate student-related

Tag list

Alphabetical list of tags here