What is blogging, exactly?

Stephany Aulenback at Maud Newton's blog has a humorous reply to some of the rather silly articles that have appeared about blogging. She also brings up an interesting point:
The terms blogger, blogging, and blog are so overused they have become pretty much meaningless. They seem to indicate any individual (as opposed to a corporation) who posts anything – anything at all -- on any sort of webpage, with any regularity.
Is there a way, or should there be a way, to distinguish between people who use blogs for linking to news (boingboing, Bookslut, The Write Hemisphere), those writing about their lives (Tequila Mockingbird, Where is Raed? wKenShow), and those based around the lives of well known personalities (Neil Gaiman, Margaret Cho, Caitlin Kiernan)? And there are plenty of other blogs that don't fit into those categories. The Mumpsimus doesn't, and that's one of my favorite blogs.
A little while back, Terry Teachout at About Last Night wrote about what makes a blog. While a good starting place, I don't think he's entirely correct in his points. (One rule I think is just plain wrong: 3. Blogs without links aren’t blogs. Blogs without blogrolls aren’t blogs. Blogs without mailboxes aren’t blogs. Half of the blogs I mentioned above would be eliminated in that case.)
In general, I'm not all that concerned. But sometimes it's hard to talk about the differences of these various places. You start introducing somebody to blogs and they say something like, "Oh, you mean like Fark." Sort of. I have no idea if Fark is a blog or something else, really. It was certainly created before blogs were around, but it would be very hard to point out the difference between Fark and a blog. In that same category, gangster of love seems to fit into the blog world, but she doesn't use a blogging engine and she insists on being called a journal, not a blog.
Is blogging becoming too vast a word? Should we categorize things into blogs, journals, news feeds, etc.? I don't know. What are your thoughts?