How Are People Making Money on the Internet?

My brother and I are both computer nuts so I was surprised when he was surprised about the ways that I told him people are making money on the Internet. For instance there is a guy who is a college student who wanted to make some money for his college expenses. He came up with the idea of selling adspace on his webpage. He calls it the "Million Dollar Homepage".

http://www.milliondollarhomepage.com/

He also keeps a blog of his progress

http://www.milliondollarhomepage.com/blog.php