Categories

The most valuable internet-sites are created by large companies and universities, but they have many areas of expertease. Creating more categories, means specializing the categories, which result in more and more places where the company or university should be listed. Usually, however, the sites are only listed in one category, which results in degrading value of the index.

The number of categories grows exponentially. You can not continue adding names of categories onto one page, so have to categorize categories. This is a really hard job. From practical experience, I found that this cannot be done correctly. A flat category list, as the Yellow Pages does, is the better solution, but not acceptable for the web.

Building a nested structure of categories will never be satisfying, hence you require a way to find a category by typing keywords: a search facility in the index.

But, any search facility has a disadvantage, which is usually ignored: we are very limited in the number of words we use. For example, the English language contains about 300,000 words. From this large set, people know a subset of 5 to 30,000 words. From this subset, only a percentage is usable as search word; only the nouns and some verbs.
If you look-up a category-name searching in Yahoo! you will see that one word gives many names, which proves the statement.