This post on using Tags and Categories on a blog was originally written by Michael Martin from ProBlog Design and updated recently by the ProBlogger team.

Categories and tags are essential for blogs and content organization for many reasons:

• SEO Benefits: Categories and tags help search engines understand the structure of your website and the topics you cover
• Content Organization: helps both your readers and you to find and navigate through your content more efficiently
• User Experience: improve the user experience on your blog by helping visitors discover related content. This can increase engagement and keep readers on your site longer.
• Content Discoverability: When readers click on a tag, they can find all the content related to that specific topic, increasing the chances of them exploring more of your content.
• Filtering and Sorting: Categories and tags allow readers to filter and sort content based on their interests, which can be particularly useful on blogs with a wide range of topics.
• Content Strategy: Categories and tags can also help you develop a clear content strategy. They force you to think about the different topics you cover and how they relate to each other.

According to Yoast SEO “When used correctly, a good taxonomy system can boost your site’s SEO. The opposite is also true: when used wrong, it’ll break things.” Check out their article on Taxonomy SEO: How to optimize your categories and tags.

In terms of content management and organization, categories and tags are almost identical.

A category system could very easily be used as a tagging system, and vice versa.

So what is it that makes the two different? And how are they best used?

Understanding and Using Categories

Categories are best imagined as a paper filing system. Each page in the system must be filed away in the appropriate drawer. There are only a set number of drawers, and so each must cover a rather wide blanket.

In your blog, categories are best used in exactly the same way:

• The number of categories should be small. Resist the temptation to add new categories because a long list of them will not be read or browsed by anyone and so, is of no use.
• Each post goes into one category. The categories are a way of giving a post permanent storage, just as the drawers do. You cannot put one piece of paper into two drawers, and in the same way, a single post should go into a single category.
• Categories are navigation elements. Categories are not simply a way of labelling posts, they are a core element of your navigation. Your categories should be factored into your site’s architecture and navigation, and displayed appropriately.
• Categories in URLs. A category represents the traditional folder system of a HTML website. Using permalinks with category names included is a good way of displaying the tiered architecture of a web site. Consider this URL – http://domain.com/category/post-name/ – If I want to return to the post’s category (i.e. go “up a level” in the architecture), I simply slash the post-name off the URL.

Complement the Categories With Tags

The most common problem with tagging is that it is used for the same purposes that categories are. Your tags aren’t categories. They are complements to your categories.

Think of tags as the colorful little page markers you might use to flick back to your favorite pages in a book. The tags don’t describe the book as a whole, instead they describe individual sections of the book.

• Use the same tags over and over again. The tagging system is useless when the tags you use vary. For instance, if you have a series of posts on writing articles, you could tag them as “journalism,” “writing,” “copywriting,” or a hundred other variations. The important thing is that you choose one of them, and then reuse it on every post you ever write on the topic.
• Tags do not need to be displayed in the sidebar. Tagging is not a part of your navigational structure, and so it does not necessarily have to be displayed in the sidebar. Why not simply list a post’s tags at the end of the post? The contextualisation will make them much more valuable to readers, and could even be used to replace “Related Posts,” plugins and such.
• The tag cloud is easy to scan. If you do use your tags in your sidebar, then use the tag cloud. A list of categories is very easily recognised because it is in a list. A list of tags will be clearly recognised as such if it is in a cloud. The cloud works because it fits a lot of information into a small space, and is easy to scan over.

Tags have a lot of potential. To a certain extent, they could be used to replace searching, if done well. Let’s say I’m interested in posts about FeedBurner. Am I more likely to get good results by searching and having every post that has ever mentioned FeedBurner returned to me, or by clicking a tag and only seeing the posts which have been specifically tagged as discussing FeedBurner?

Categories and tags are both very useful assets, provided they are each used for their own purpose. Are you using tags on your blog? Will you be using them in the future?