A public journal is the best way of putting it. There are a million things that can go into blogs. Personal development, issues with family, needing to vent about something that you don't necessarily want to be debated about or even "discussed" but would maybe just like some support or helpful comments on. Perhaps someone wants to update with some news, but it doesn't warrant the front site or even a thread, really. There are a plethora of things to write about.

For instance, I'm thinking about doing an FF foodie type of blog here soon. Where does that go - the front site? Doubtful, because it's not really news or anything really related to Final Fantasy itself other than in reference. The art threads? Also doubtful. Threads in GC? Who wants to see me posting pictures of food and recipes in a main forum thread once a week? Also doubtful.

They aren't necessary, of course. There's no reason to have them other than to be involved in eachothers' lives a little bit more and for the user to post miscellaneous content that doesn't "go" anywhere else.