For those of you who don’t know tagging is a little bit of a phenomenon sweeping the web right now. The idea is that any content can be “tagged” with a series of words which will describe it and then you can reaccess that content through the words.
To my mind however tagging is a very old thing in terms of the web. Tagging is a way of attaching the most relevant keyword/keywords to a set of content. Effectively anchor text is just a form of “tagging” by webmasters and titles for webpages are just strings of tags the owners have put together.
Auction sites, classified sites and personal sites effectively receive thousands of tags a day. Self learning category structures could be created really powerfully from this stream of user generated tags. All this data is exposed to any API programmer and someone with the skills and interest could create a product search more powerful than any of the Kelkoo’s etc. out there right now with millions of small businesses and individuals automatically helping them with accuracy without even realizing it.
I suspect I may post more on this later since I am now planning to give it a go in a small category of listings on eBay.