Earlier I discussed tag cloud algirhtim/logic/formula and talked about linear and logarithmic interpolation. The difference in visualization can be viewed at ToCloud.com that takes any URL and converts into a tag cloud with various options for interpolation and sorting. In addition, there is an interesting concept of comparing two pages in a single keyword cloud. And also the ability to take tag summary pages from del.icio.us or slashdot and turn them into clouds to give clouds within tags or what is referred as sub-tags. Even daily news can be converted into keyword clouds.