I’ve had a few people, inside work and out, ask me about the difference between tags and categories when it comes to blog posts and in particular the WordPress platform. I thought I’d put my thoughts about this up.

What is tagging?

Let’s go back to basics.

Tagging, in the context of blogging, is the attaching of keywords or phrases to a blog post.

By attaching keywords to a post, the author can provide some clues as to what the post is about, perhaps even in words that he might not have used in the post itself. For example, a blogger might well write about teaching a class and not once in the post use the word “education”. Since the post is about education, it would make sense to use this as a tag.

This is why tags are considered “metadata” – they are data “about” the data.

On the other hand, that blogger might write about education in every post – perhaps this is his educational blog. So the tag “education” would be redundant. The most effective tags help differentiate a post from other posts.

Most blogging platforms allow readers to navigate by tag. You can, as a reader, click a tag on a post and see all the other posts that have that tag. That’s why if every post shares a tag, that tag is not really adding any value; if all or the majority of your posts have the tag “education”, the reader will see just a replica of all your blog posts when they click on it. Tags, as a navigation tool, act as a filter.

Some blogging platforms offer or allow for a feature called a tag cloud. This is a representation of all the tags in your blog, and ordinarily the most frequently used tags are displayed on a relatively larger scale than those tags used less frequently. The cloud thereby acts as a navigational tool for the whole blog and as a quick visual indicator of what the blog is about. The tag cloud is actually a form of graph.

It’s important not to confuse “tag clouds” with “word clouds”. Word clouds are graphs emphasising the most frequently used words in a piece of text. You can produce a word cloud of any text using the free in-browser tool, Wordle. A word cloud of a blog may or may not look similar to its tag cloud. Remember, tags are an opportunity for the blogger to give weighting to or use keywords that might not be prominent in the posts themselves. A word cloud can feature words like “the”, “and”, “an”, and other very common words that don’t actually tell you about the content of a post. While you can create a blacklist of these common words so that the word cloud gives a more helpful overview of a post or a blog, the tag cloud is a much more deliberate representation of what a blog is about.

What are categories?

WordPress has traditionally featured a component called “categories” which many would, and sometimes do, use like tags. Categories, in WordPress at least, are different in that they can be organised hierarchically.

In WordPress, categories are mandatory – if you don’t explicitly give your post a category, WordPress will give it the category “uncategorised”. At least one category box must be ticked.

Like tags, however, you can have more than category in a post – or rather, your post can belong to more than one category, and this grammatical distinction is I think indicative of how they are to be used.

Later WordPress introduced tags as well. On the WordPress support page, “Categories vs. Tags”, they say that tags allow for describing a post in more detail, since category lists that authors were creating were getting too long. But that has led to confusion about how each should be used.

What’s the difference?

  • Whereas tags are a flat list, categories can belong to other categories, effectively making them sub-categories.
  • Categories (in WordPress, at least) are mandatory. Tags aren’t.

But these differences don’t really tell us about their different uses.

If categories are mandatory and tags are not, is it better to use categories to start with and then use tags out of necessity?

This to me seems like a waste of possibilities for organisation.

If you look at an article on whether tags or categories are better for SEO purposes, the advice is simply to think of end-user navigation rather than SEO, as SEO will result form this approach anyway. So I think it’s worth putting some thought into this from a user perspective.

My own feeling is that categories should be planned up front, whereas the list of tags you use can grow organically. Here’s why.

Categories can be used to denote projects or products, or even sub-projects/products if you are creating a hierarchy of categories. You can see an example of this on the blog for the University of Reading’s DEVELOP project which I was involved in a couple of years ago. Tags can then be used to address the problems or topics or tools specifically covered in each post.

Perhaps more generally and more usefully though, I feel that categories should be used to describe the “type” of the post. As I said earlier, we can say of a post that it belongs to one or more categories, just as a category itself can belong to an even higher category. Tags, on the other hand, are like keywords appended to a post – they belong to the post, rather than the other way round. Tags are the terms one might search for.

What do I mean by “type”? One might, for example, use a blog to write technical posts, like I do, to comment on certain situations, to review certain products or items. Say I have a number of film reviews on my blog. I would not tag each review with the word “review” – such a tag would not tell anyone about the specific contents of a post as, say, the tags “Stanley Kubrick” or “Ridley Scott” would. Rather “review” is the type of the post so I would create a category called “Reviews” and make sure my reviews belonged to this category.

I might then create sub-categories and organise my posts into “Film Reviews”, “Book Reviews”, “Music Reviews”. Other categories I might set up are “Commentary”, “Politics”, “Technical”, “Philosophy”, etc. All these categories would hopefully identify the type of the post so that readers in the mood to read a film review, any film review, would be able to find it whilst readers looking for any posts about Stanley Kubrick would be able to use the “Stanley Kubrick” tag to find all the relevant posts, whatever category they belonged to.

The category should refer to the format or conventions of a post (one can expect from a review certain information and a certain tone), whereas the tag should refer to the contents of the post. This hopefully illustrates what I see to be the difference between the two and how one could potentially use this to organise one’s writing.

What next?

Scriptogram, the blogging platform I am using at the time of writing, does not have a feature for categories but as I continue to explore channel-neutral writing and content management, I hope to factor “categories” into the metadata I create for each post.

I would also like to revisit actually writing some reviews and other types of posts, as I used to on my old personal blog, Small Boats. I have a pile of books and topics ready to write about; I am now justing finding the time and investigating the appropriate space.