A tagline is a chronological tag cloud. Using a series of PHP scripts, the tag clouds are generated from a single XML file. As in most tag clouds, relative font size approximates word frequency. Larger terms appear more often in the corpus; smaller terms appear less often. The rule for hues is somewhat different. Tagline assigns darker hues for terms that appear over a long period of time in the series or, that is, for terms with greater persistence. Newer terms and terms appearing for the first time are assigned a lighter hue.

The tagline you see here works with the monthly archives of Earth Wide Moth. Each cloud in the pattern corresponds to a given month's blog entries. Move the moth icon along the slider bar to see the cloud for each month. Click on a term and you will launch a search process that will return all of the entries using that term at this site.

Tagline was developed by Chirag Mehta. His presidential tagline is one notable application of the process. It has also been used in Thoughtmesh, in Dave Lester's American Studies "visual historiography", and by reporter Todd Bishop to present a company history of Microsoft as a series of clouds. The PHP stemmer was developed by programmer Richard Haynes; the slider comes from Erik Arvidsson. Mehta includes a similar "aging tagcloud" at his own blog, which is where I got the idea.

Tagline is available for use under a Creative Commons 2.5 (Attribution) license.