Bruce, I don't have an answer but do share your curiosity.  I actually invoked the blog module and wrote my first blog entry.  However, the page, the way it presents, is excessively busy.  It seems to invite lots of visitors to become bloggers but it's way too complex for right now when all I want to do is have folks go to that page to see my blog.  So...my main point is, you're not the only one who has this question.

One other thing: if anyone can point us to documentation on the other modules, that would help, too, as some are more self-explanatory than others.  Thanks.