Why not a blog without categories?
Labeling things and people has always been a cause for concern to human beings, so why wouldn't you just get rid of labels when blogging?
I know, this might seem to many as a controversial decision to be made, and it is actually, but think a little bit about it.
Possibly it is worth considering to take such approach if your web site or blog is dealing with dozens and dozens of different categories? This happened to me until I found myself managing an endless list of items like this one:
And many, many more.
Can you imagine? I couldn't just keep the focus and decided to remove all categories!
Just as a disclaimer, I wouldn’t really recommend you do this too, no matter what, with no good reason behind. In fact some users love tag clouds as well as labeled, categorized content!
A blog without categories is an awesome experiment to be put to the test, similarly as with disabling comments, removing cookies, or writing articles in different languages at the same time omitting translations deliberately, as if addressing a multilingual audience as opposed to translating the articles one by one.
I suppose at the end of the day it's all about being practical and simple, especially when your website gets to a point that you'll have hundreds of categories. In that case it is probably better to just let users look for content in a search box.
Debate of this kind will always be good to exercise, remember what the theory says: Content, not labels, is king.
Thank you for reading, and I hope you'll stay tuned to see how my SEO experiment on removing categories goes on.