Phydeaux3 has come up with a really creative and easy-to-customize widget that displays tags on your page. Tag clouds are described on Wikipedia as "weighted":
To get the HTML changes, follow the directions on the phydeaux3 website, it's not difficult.
A tag cloud (or weighted list in visual design) can be used as a visual depiction of content tags used on a website. Often, more frequently used tags are depicted in a larger font or otherwise emphasized, while the displayed order is generally alphabetical.