Tags are an interesting look at how the human mind works. We are programmed to create shortcuts to identify objects and ideas. The subjects in our OPACs are one way of labeling ideas, but not all people have the hierarchical way of looking at things that delights traditional catalogers. (see my earlier comments here) What I like about tags is that they allow for a multitude of entry points for finding information. Just as I might be referenced by my given name, job title, a kinship term, a hobby or physical trait, each one giving a fuller picture of who I am and allowing various people to share their knowledge of me, subject tags allow people coming from different backgrounds to access the same article. Looking at the tags that someone else has used for an article allows me to see new ways to classify the information. That turns upside down the way we present knowledge to students. Often we tell them the subject, then the topic and then the specifics. We test them expecting one right answer. We ask them for the main idea as if there could only be one. What if we give them an article to read or listen to and have them tag it first as individuals and then sharing their tags? One article I read (unfortunately before I began using del.icio.us) pointed out that as more people tag an item, the irrelevant tags become statistically insignificant. If a whole class fails to find the labels we expect, maybe we have failed to give them the right information.