Images: Playing tag on the Web

Daily Kos is one of the newest players in the tagging world. It recently implemented tagging, and founder Markos Moulitsas says it has helped bring order to the untold number of documents on the site.

Photo-sharing service Flickr is one of the tagging pioneers. The service implemented tagging last year, and the feature now helps users find the images they are looking for from among the more than 50 million photos the site hosts.