From Wikipedia:

A tag cloud (word cloud, or weighted list in visual design) is a visual representation for text data, typically used to depict keyword metadata (tags) on websites, or to visualize free form text. ‘Tags’ are usually single words and the importance of each tag is shown with font size or color. This format is useful for quickly perceiving the most prominent terms and for locating a term alphabetically to determine its relative prominence. When used as website navigation aids, the terms are hyperlinked to items associated with the tag.

CSGPN uses tags as a means to help identify topics and issues that can be covered across more than one project, as well as providing a quick means to search the website for popular topical content. The tags used on our site are in order of prominence, not alphabetical. This indicates how many entries on our website have been tagged with these keywords. As more entries are tagged, the keyword in the Tag Cloud will appear to grow in size. This assists members in searching our site for the most popular items and terms from our content. Tag clouds aren’t a replacement for the Search feature, but provides a fast means to access commonly searched content.

By placing the mouse cursor over the top of a keyword, you’ll see a Tip/Hint as to how many entries are available with that particular Tag/Keyword nominated.

Clicking on a keyword in the tag cloud will present a list of entries that have been marked appropriately, for example by clicking on the Fax or Bulletin keywords you will be given a result page listing all available entries on the site with these tags.