If there is anything I hate, it is trying to categorize things. I go into Blockbuster, and I can never find what I’m looking for because I don’t know if “Desperate Housewives” is a Comedy or a Drama. With someplace like Blockbuster, it is hard because there is only one physical thing and it can only be in one place, so you can only label it with one genre.

That problem doesn’t exist with their digital things like MP3’s and Digital Photos. Through the wonders of computer Programmers, you can apply many labels to one things and you computer program and can make it appear in all those places.

In typical database design, you would come up with all the possible attributes of an object (or at least the ones you can think of). You would then go through each of the possible attributes and see if you can enumerate all the possible values for it. For example, a DVD may have attributes like Genre, Actors, Studio, Release Year. And attributes may have values like 2001, Drama, and Universal. But you can also see that you can’t enumerate all the possible values for some attributes (there are always new Actors and Studios, and despite what late night television tells you, time keeps on marching). For these attributes, you would either spend a lot of time updating the possible values, or just give up and let it be any possible value. That is pretty much what a Tag is.

A few sites have started using Tags to allow you to categorize digital things. Flickr.com allows you to tag the photos you upload. del.icio.us allows you to tag links in a shared bookmark (Previous Post). And Technorati.com allows you to tag your blog entries. Rather than going to typical organization route (like in the previous paragraph), they don’t even bother to come up with attributes. You just come up with a handful of tags to describe the item (like 2005 DisneyWorld January Florida) and you are set. The only restriction on the words use for Tags are that they should be one word and shouldn’t be something common like “of” or “to”. And really, the only reason for the one word restriction is to make it easier on the user to enter in the tags (you don’t have to remember to put a ; in between each tag, for example).

Trying to find the items you (or someone else) has tagged is really simple. Just come up with a few possible tag names and the search engine just has to go through and find all the items that have those tags.



You can also browse the items by Tags. Flickr.com provides an interface (pictured here) that allows you to browse by Tags that have been applied to the most items. The bigger the text, the larger the number of items contained with in. You could even imagine doing this through multi-levels to find pictures from Japan taken in 2004.

Sometimes there is much power in simplicity.