Blogs are designed to cater for private or multi-person thoughts. People can use blogs for any purpose in relation to posting their thoughts, Blogger was bought by google in 2003 and is used by millions of people all over the world.
I've recenetly taken a serious liking to Blogger, at first I couldn't understand why blogger was so useful, but through the weekly exercises posted by damian and the opinions I get from other classmates, I can really see why blogger is used in the web business.
Blogger also creates a virtual identity for people, giving them something they can work on and improve, through CSS and creative spree's.
Here is a definition of blogs.