I’ve been experimenting with different themes lately and as much as the WordPress offers some great ones I find I like the darker print with the wider multi-columns. There are only about 3 themes like that and Sandbox  is one of them. For those of us that share vasts amount of information we need more space to present the content in a pleasing manner.

-when there are many categories to choose from- it is best they are spread out with good visual direction-

WordPress Faq. “The difference between tags and categories

We used to have just categories.
These allowed the broad grouping of post topics but when you wanted to describe a post in more specific terms you had to use more categories. That lead to very long category lists inside the blog, very long lists in sidebars. It was also confusing in that what we said were categories others said were tags.”

read more here So now we have tags as well.