The Business Directory search page within Tendenci contains a "tag cloud" listing that helps users visulalize the amount of content within a particular category. Often the value of "weighted text lists" is misunderstood as "a jumble of mixed-sized fonts". Instead the developers of Tendenci see the lists as an easy means of communicating the popularity of content.
Visualization is an important theme in Tendenci. The value of human communication and interaction is weaved through every part, including putting tag clouds on Business Directory listings to help communicate the value of the content.
For more on the theory behind tag clouds, I suggest reviewing these powerpoint slides by Rashmi Sinha. Rashmi put together some slides that help to explain the theories behind tag clouds. Here is also a link to Rashmi’s site: http://www.rashmisinha.com/.