Categories are best used to organize your content into groups based on the topics your website covers. For example a website about sports might have a category for each type of sport it features.
These categories then make it easier for your readers to find more content from the same group, helping them to discover more of the articles they are interested in. This in turn increases the time your visitors spend on your website, giving you a greater opportunity to connect with them and move them towards the goal of your website.
That goal could be subscribing to your newsletter, buying a product, or signing up for your service.
Furthermore, categories are hierarchical, which means you can have sub-categories. To continue the sports analogy used earlier, each category for the individual sports you cover on your blog could have multiple sub-categories for the different leagues, classes, or genders that you write about.
While WordPress gives you the ability to create as many categories as you want, it’s best to limit the number as much as possible when you start your blog. You can then add more categories as and when they are required, as your website grows.
Although it’s impossible to state what the right number of categories is, if you take some time to plan the content of your website before you get started, you should notice some obvious candidates for categories emerging. For example, if you were creating a sports blog, some topics you might want to cover could include: football, basketball, baseball, and golf.
By creating a set of categories to cover the main topics you plan to write about before you start writing your blog posts, you can avoid creating too many categories that end up only containing a few pieces of content each.
The downside of creating too many categories is that it dilutes their effectiveness. When used correctly, WordPress categories can be a great way to organize your content more efficiently. But too many categories with only one or two posts in isn’t helpful to the reader, whereas a category that contains lots of related content makes it easier for them to find more content on the subject they are interested in, rather than leading to a dead end.
When creating categories, if in doubt, keep your original set of categories more general, and then get more specific as the scope of your blog increases over time.
Just as you can create multiple categories, each post can be assigned to multiple categories. While it’s impossible to state that a post should only be submitted to a certain number of categories, minimizing this number should be your goal.
If a reader clicks on one category with the aim of viewing all the posts on that topic, and then they click on another category and see the same posts are also assigned to that category, it can be confusing to them, defeating the point of categories altogether. Therefore cross posting content to multiple categories should be avoided in most cases.
If you find you are creating posts that fit perfectly into more than one category, perhaps you need to merge those two categories, or a create a new category that better describes those posts.