A tag cloud is a list of tags, where the font size of each tag is larger or bigger depending on its weight. Weight in tag clouds can be represented in three different ways:
Source: Tag clouds at wikipedia
There are several opinions on how tags should be ordered. Examples of ways to order tags are:
Tag clouds helps visualize semantic fields; how some categories have greater importance than others.
It can also help give an impression of what content is to be found on a given site. Which categories of content is the site focused on?
Tag cloud at Flickr.
3D tag cloud - must see in real life. Click the source to view it: "coda.co.za":http://coda.co.za/blog/
The tag cloud at delicious.com has listed its tags with alternating sizes, but also alternating colors where black is the heaviest and light grey is the lightest.
The tag cloud at piano-faust.de incorporates 5 different colors for the tag text and also 5 colors for the tag icons. The tag cloud is simple designed in corporate colors by CSS.