Categories and Tags in Posts
When you write an article, it is generally good form to place that article in some category. The categories are YOUR choice. You can create them en masse at the dashboard/posts/categories function. Or, you can create them as needed by selecting the “+ Add New Category” button in the post editor. Categories can be anything you want. Examples might be: Technology, Featured, Devotions, Wisdom, Family, etc.
Categories can also be created in hierarchies. So that “Devotions” might have Morning, Noon, Evening as SUB-Categories. Again, these are just demonstrations/examples of what you MIGHT want. Create them to fit YOUR content. Ask yourself, “Overall, how can I order (or organize) the articles that I write?”
In time, after you have created many articles, users can see all the articles in a particular category of articles on your site. It will also make it easier for you to determine if/when you wrote on a particular topic.
Similar to “categories” are the “tags” which are also attached to an article/post. Tags should be reusable (something that you would use to tag another article at some time) but they are less defined than categories.
Example: If you are writing about the riots in Ferguson, MO, and placed the post into the “Current Events” category, you might use “racism” and “violence” as tags. Later, users could view all the articles in the “current events” category or search for the “violence” or “racism” tags and they would find your article.
The WordPress software (with the appropriate plugin) will create a “Tag Cloud” (see the graphic, “Tags” or just look in the footer of this site) that you can place as a “widget” in the sites sidebar. The cloud will list the top tags that you have used and the more frequently you have used a tag, the larger the font of the tag in the cloud.