Difference between Blog and traditional websites

Link: Video: Blogs in Plain English | Common Craft – Explanations In Plain English.

For a long time I have wondered: What is the difference between so-called "personal website" and "blog"?
This video, especially at the end of it, gave me the epiphany: the openness.
Blog is open, but "personal website" is not. This is largely a matter of attitude than technical innovation, but I think what Blog has done is to open up the communication, or the potential of communication, on the internet – in the "personal website" area probably people still used the Internet as closed mediums with flexibility and faster access.
Blogging changed the attitude, which IS the real, frightening, change. This is exactly why blogging was attacked by the early adopters of the web – they felt that their pioneering position was violated. And of course they were dead-on, except that the violaters, bloggers, were showing what these early adopters should have done.
Isn’t it frighteningly annoying when newcomers show you not only they can do your job better, but worse – they show you that you weren’t getting "it" after all.

By the way as a user interface designer I am wondering  why on earth Common Craft’s presentations are so easy to understand AND addictive. Hats off.