How is blogging different?

This is my very first blog posting, so I thought I'd start with a broad question and see what kinds of responses I can garner.

So here's a question for all of you out there: how is blogging different than creating your own website? I've read a lot of articles and posts about famous bloggers or famous blogs, but how is this any different than if those people had just created their own websites and updated them every day with new pages?

Is it just the fact that people can respond and reply to articles and posts? Is it because a blog is free?

And, how does the Wiki world play into all of this? Is Wiki simply a blog without state that anyone can keep editing over and over? Is there any way to combine the two technologies?

What do you think? Why blog instead of creating your own website?