Is there a power law of category use?

I have been thinking a lot about categories over the last week or so. It started by Thomas sharing the work he has been doing to build a category index page, whose design I love. I started to realise that I like to put a lot of my blog posts in one of few categories: moments of joy go in one category, slices of life go in another, posts about coffee go in another.

As a result of all of this thinking about categories, I fixed my category index page, which has been broken for a few months. I added a count of how many posts are in each category so I could see how I use categories. I noticed what I had felt from how I use categories on a day-to-day basis was true in the data: there is a heavy concentration of posts in a few categories, and then a long tail of other categories.

I created a chart in Google Sheets to visualise the trend, charting all 63 categories I use at the time of writing this post:
A chart showing a power law trend in the use of categories on my website. Almost all of my blog posts are categorised in one of the top 10 categories. ALTA chart showing a power law trend in the use of categories on my website. Almost all of my blog posts are categorised in one of the top 10 categories.
Thomas confirmed the trend applies to his website, too, which has me interested in whether others, too, have long tails of categories.

I think there are a few possible reasons for why my category use is in this way.

First, I intentionally like to keep the number of categories I use to a minimum. I feel that expressiveness is an attribute of a category which can vary. A category can list posts that are part of a series, like my IndieWeb Carnival category, or be an umbrella for a whole genre of writing I do, like my Stories category (which include some of my poetic prose). Indeed, I think categories serve both an organisational and an editorial use on a page: they help me find my posts, and also add a label of where I think the post fits into the rest of the website.

Second, I don’t remember a lot of the categories I have created. It’s easier to remember fewer than many things.

Third, my category use is perhaps influenced by the fact that the tool I use to publish blog posts, Ghost, only has a limited history of the categories I have used.

While I try to minimise the number of categories I use, I do create new ones when I feel like having a page that lists posts in the category I want to create would be useful. For example, I recently created a category called Bear Blog Carnival so I can aggregate all my contributions to that event; I have a category called Artemis that groups all my blog posts in that project; I have a category called “New Things” that followed a challenge I did to try and do a new thing every day for a week.

An interesting side effect of having categories is that they remind me of different projects I have done, like my guest writing for a Scottish coffee roaster, and my two separate one-off attempts to try week notes. It was also interesting to see that I have published almost an equal number of posts in the IndieWeb and Life categories. This matches what I think about my writing: I love writing about technology, but I love writing about the world around me too.

If you do any analysis on how you use categories, I’d love to read what you write! You can send me an email with any ideas or thoughts you have.
Others' analyses
A few people have done analyses of their blog category use since I wrote this post. Here is a list:
Thomas (link added earlier in this article, too)Luke
If you write a blog post with your own analysis, email me and I will add it to the list.