Tag clouds are a becoming a popular way to show popularity (or frequency of occurance) of a word or phrase on the web. Here's a cool site I stumbled accross that creates tag clouds by aggregating stats from a variety of other web sites (Google, digg, etc.) to give a visual representation of the popularity of certain words and phrase in real time in the form of words that are printed in larger font according to how popular the word is. Click on the word and see what stories contributed to the word being big. Cool.
I probably wouldn't use it on a regular basis but it is interesting. As I write this Apple, Microsoft and Google are the biggies but it's in real time so when I was checking it out a couple days ago Apple was the only really big tag.
Okay, now I'm curious so I am going to go see what's up with these guys. See? It works!