1. A method of assessing value of tags in a collaborative tagging system, the method comprising: monitoring user interaction with each of a plurality of tags, wherein each of the plurality of tags has been previously associated with at least one artifact of the collaborative tagging system; for each of the plurality of tags, determining a measure of value for the tag according to user interaction with the tag; and outputting a list of at least one tag and an indication of the measure of value of the tag.