Although it is old, I still think that Rebecca Blood's Weblogs: A History and Perspective is still the best explanation of what blogs do and what they mean. For something more recent and bare-bones, Walt Crawford's article Blog or wiki--which tool to use does a nice job of laying out the features of blogs (and wikis), and although it's somewhat library-focused, I think the basic information would still be useful.

I'm trying to find something that relies even less on hyperlinks, since those are frustrating without the internet.