Rashmi Sinha put together A cognitive analysis of tagging (or how the lower cognitive cost of tagging makes it popular) that I found to be illuminating.
The rapid growth of tagging in the last year is testament to how easy and enjoyable people find the tagging process. The question is how to explain it at the cognitive level. In search for a cognitive explanation of tagging, I went back to my dusty cognitive psychology textbooks. This is what I learnt.
The short version: tagging is a simpler process because it lets us annotate something with all the concepts that it fires in our brains. Categorization forces us to pick one of those concepts.
Rashmi covers several additional topics where tagging comes to the rescue. All of these topics are covered with reference to various cognitive concepts, which I found instructive.
- cultural consensus about how to "categorize" digital media, particularly when it is personal.
- not only do we want to file for today, but we want to be able to find it in the future. Multiple tags help reconnect an item when we want to find it in a slightly different context.
- might want to tag with multiple kinds of descriptors: topic, style, type, physical characteristics, etc.
- re-categorizing is expensive, changing tags is easy.
One idea that isn't covered in the main text is something I've noticed about adding tags to my blog posts or when I add items to my del.icio.us or flickr. I want to use tags that I will remember, and there are some items that I want to tag for the greater good. I want to be sure to use tags that will resonate with other people, so they can find stuff. For instance, I have gone with the convention of smashing a person's name into one "word" (firstnamelastname), though I have seen others use a + (firstname+lastname).
Be sure to read the comments on the entry, as they go into more detail on some of the points she makes.
[Thanks to elearnspace for the pointer.]