Tags vs Categories

Here I want to write a little about Tags and Categories and what they mean, and when you might want to use each of them.

When blogging, use categories to add internal structure for you and your readers. And use tags to join an unstructured global conversation around common topics.

More about tags and categories on wordpress.

We’ve all dealt with categories a lot; fill in a form for insurance and somebody is going to ask your occupation. Tricky. I never get anything that matches quite what I do — the answer is always somewhat of a compromise. But the designer of that form is really happy, because they make you fit into their list of occupations — their taxonomy. That’s categories. Somebody makes up a list and you have to fit in. The world is full of famous taxonomies — the classification of all the species on our planet is the biggest and most famous of them all. But think of the Dewey-Decimal system in the library as well.

When you’ve got your own blog, you can make up your own categories and put your own posts in them. You’ve got your own taxonomy to play with and you can use it in lots of different ways to classify blog posts.

Now, tags are a different question born from a different problem. Say me and fifty thousand others get together and try and hammer out the categories we need to describe all the websites on the internet or all the knowledge on the planet or something nice and humanly complex. Will we reach agreement on some set of categories? Maybe a little. We’ll run out of time, argue like mad over lots of individual distinctions and end up getting nowhere.

Tags evolved to solve this problem. Tags are just words, anyone can make them up, use them and apply them. There’s no rule book or plan of categories or hierarchy controlling them.

This works in the real internet world because people tend to use similar tags for things and it is possible to search for them and cluster them together. Lots of stuff gets tagged. Blog posts, photos on flickr, events, videos on YouTube and so on.

So, you can tag your posts with some words, and if others on the internet tag their stuff with the same word, then a tag-based search engine like technorati.com can put them together.

For example, the top popular tags at Technorati at the moment are: music, iraq, al gore, britney spears, and so on.

Go deeper on tagging at wikipedia in the Folksonomy entry. A folksonomy is, I guess a taxonomy made by folks.