I think the tag cloud is self explanatory in the sense, the font of the individual tags depends on the amount of content under a particular tag. It's a visual r

I think the tag cloud is self explanatory in the sense, the font of the individual tags depends on the amount of content under a particular tag. It's a visual representation of the category system where the amount of content in each is represented by a number in brackets in front of each category. Both these techniques have their own pros and cons as one is more visual while the other asks the user to find out where he wants to go. I think a combination of both might be the optimum solution, where the content is provided under tags which are pretty broad and category and sub category takes the user deeper and is more useful for users who are looking for specific information.