TAGS and CATEGORIES are a great help to your readers.
The whole reason why tags, categories and search widgets are used on blogs is to serve one purpose — help your readers locate the information they want on your blog. Readers want quick and easy solutions; too hard and they look elsewhere.
While aim of using tags and categories is the same — to help readers locate information — they are used differently.
Categories are like chapters of a book; they give a general overview of the topics you blog about. Whereas tags are more like the index at the back of the book and explode the topic into a million bits.
Categories and tags are displayed in your blog sidebar using the categories widget and Tag cloud widget.
Here are some of the tags that you will be using in class.