Is there an add-on "tag clouds" or "keywords block"?

I really appreciate XenMedio that contains keywords tags in every page that each terms are clickable then if clicked brought to you a page result related to the keyword.

It's a great SEO addon for videos.
I would like to have something similar for the threads.
With each tag clickable, and then display the threads that contains the tag/keyword.
I know, there is the Azucloud, but it only produce tags.

I've seen some SMF forum, running the same feature.. tag searches.
Really SEO boost.

Although, they use characters instead of keyword as default.