HughMungus - 8:32 am on Jan 20, 2004 (gmt 0)

Is the main advantage of blogs merely that they offer a simple, quick and easy way to add content?

Yes. It lets people have web pages, post images, post audio (see my profile), etc. extremely easily (e.g., you don't have to learn a lick of HTML or even know what an FTP server is much less how to use one). The other bonus is that you don't have to have a web host to be able to put stuff online.