_Thomas is obsessed with information structure (among many other things) and makes a living feeding his passion of building usable and reusable information delivered to Web browsers of all kinds. Thomas has been practicing his craft for dog years and has spent the last 10 years working in and around the web as a webmaster, information architect, interaction designer, director of internet product development, and web program manager. He can be found at www.vanderwal.net and www.personalinfocloud.com._
We all grew up knowing about tags. We had tags in our clothes, we had them on our holiday presents, we played a game called tag, and some even used spray cans to tag their turf. All of these uses of tag have different meanings, but unless we understand the context and/or the person using the word tag we do not know what they mean. This can be a problem with tagging on the web, but like everything else there are two sides to the story and there are some great benefits from tagging, if it is done well.
###The World is Flat
Tagging is a non-hierarchal (for hierarchies think of the old Yahoo! directories) means of organizing information or objects on the web. Information is found through associative correlations or inference. In a hierarchy one would go to people, then film, and then actress to find Cate Blanchett. Using tagging one could use actress and moviestar to get a similar result.