For me, very much so. My site (in profile) is not exactly a blog, but it lets me say things that might otherwise bore people in personal conversation, and then I can just refer to it briefly if a longer topic comes up, and they can read later or ignore if not interested. That has saved my wife from having to listen to yet another repeat of me going on about a favorite topic.

Plus, there are just things I want to say that are important to me. It is an outlet. I use my personal organizer software to make the writing easier, then export it in an outline form.