According to Netcraft's Rich Miller, there are 100 million sites with domain names and content. This is double (50 million) in May of 2004.
While this includes blogs, I'm assuming they're removing splogs and sportals from the count.
From the article:
So will a URL someday be as common as a birth name and a Social Security number?
I'm thinking "yes".
CNN: "Web reaches new milestone: 100 million sites".