Tags, Taxonomies, and Categories

Musings on the classifications of all (or some) things…

Most people are familiar with categories in web-based thingies. Look at Yahoo! or the Open Directory Project, or applications like Movable Type. They have hierarchical categories, where you create a category, then create categories within those categories, and so on. When you do it yourself in Movable Type, chances are you’re just guessing at how to best organize things based on your own experience and data, which is fine, it’s your view of things. In theory though, Yahoo! or the Open Directory Project have some sort of “well defined” categories created by experts, or some such thing. This is also fine… The problems come when you want to have a similar category set, so that what you call “Hardware” (Computers?) is what someone else calls “Hardware” (Hammers?) right? Syndic8 uses the Open Directory Project (DMOZ) categories, as well as some others.

Syndic8 uses multiple sets of categories, which is really more like taxonomies. At least by my understanding of taxonomies. I’ve always though of categories as sort of the “common” or “average” way to classify things, while taxonomies are more of the expert’s view, where more thought goes into it. That might not be the case, but I’ve viewed it that way. I think developing taxonomies as being more involved, since you can have multiple taxonomies that are completely separate from each other. For instance, you might have a taxonomy that works like your average category set, but them might have a taxonomy that works like a rating system, with G, PG, and NSFW categories. Taxonomies seem to allow another way to organize and classify data. (Drupal has a really nice taxonomy system.) I’ve often wished iTunes allowed for multiple taxonomies. I’d like to have a rating system for songs that had “kid-safe” and “explicit”, or perhaps “silly” and “serious”. Multiple classifications if you will… Perhaps TuneTags can provide that.

TuneTags seems to take the tags approach, like or flickr. Tags are a bit different, and somewhat like keywords, in fact they may be keywords, but in a simplified way, which makes them more powerful. Tags appear to be a single word, all lowercase, and you add multiple tags by just space separating them. This is brilliant in it’s simplicity, and can be powerful if presented properly. shows you the most active tags in the system, and while entering new data into the system, shows you all the tags you’ve previously used, with a count of usage. This seems like the fastest way of categorizing things, and with the ability to get a list of the most active tags, it’s easy to align your categorization with others, if you so desire. (John Udell is doing some interesting things using tags and flickr also provides a list of the most popular tags, which, just like, really moves the whole idea of “social software” forward, by making things easy and powerful. Those two extra things, providing a list of the most used/active/popular tags, and the display of your previously used tags are key to making things work – I’ve used systems where there is a field to enter keywords, but without those two things, it falls short of accomplishing what it really could accomplish.

This is all just off the top of my head, so if you think I got anything wrong, or missed something, let me know