You see these tag views on quite a few blogs and I'm curious what SO used in their recent tags implementation...
I'm thinking more along the lines of the jQuery tool used or however else it was presented...
Looks like it renders as straight text, divs, etc. with styles set on all of the different words. A jQuery plugin can facilitate this for you...
*Note* Please don't upvote this and screw up the bounty system.
Fairies and unicorns collect the tags from all of the posts. Then they add up occurrences of the words and make them bigger if there are alot.
After they are done, they take hand-fulls of the words and toss them at the web page.