I recently heard Anil Dash put it in this very simple way:
“A blog is a way to connect with people you care about.”
And it has nothing to do with technology, feeds, etc.
It’s quite another approach compared to my own (alternative) definition of blogging and the flaw would probably be that it can be applied to many other things as well (forums, IM, MySpace, etc.) Still, I like it. It kind of makes sense to look at blogs in this social way.
Furthermore, Anil would explain that we hardcore bloggers tend to think that most people would like to talk to hundreds of thousands of people through their blog. Actually, most of them don’t! They regard us as somewhere between strange and psychopath. (And I do remember my girlfriend having that exact same reaction when I first told her about my blog… )