Why is the internet so full of stuff you don't need?

The internet is accessible to a lot of people and many of those people put things on it. WikiAnswers is a very good example of this. There are many repeated questions, many questions that have already been answered and many questions for which answers could be got elsewhere on other sites. Many of the things on the internet are of no value to some people, so you might not need them, but of value to others.