This week's topic is essentially a merging of the past two weeks--what happens when bottom-up emergent behavior meets the top-down semantic web?

One answer to that question is something that's being called "folksonomies," or "emergent vocabulary." It's what happens when instead of providing a controlled vocabulary or taxonomy, you allow users to simply describe their own data and share that description with others.

Two systems using this approach that are currently enjoying a lot of popularity are the social bookmarking system del.icio.us, and the photo sharing system Flickr.

Both allow people to store information in a public space that in the past was limited to individual access. Both allow people to assign free-form tags to items in the system. And both allow people to view each other's data and tags, and to shift their views of information based on both people-centric ("show me all the people who find this item interesting") and data-centric ("show me items tagged with this term") approaches.