Scott Adams:

As with most of my life decisions, my impulse to blog was a puzzling little soup of miscellaneous causes that bubbled and simmered until one day I noticed I was doing something. I figured I needed a rationalization in case anyone asked. My rationalization for blogging was especially hard to concoct. I was giving away my product for free and hoping something good came of it.
I did have a few “artist” reasons for blogging. After 18 years of writing “Dilbert” comics, I was itching to slip the leash and just once write “turd” without getting an email from my editor. It might not seem like a big deal to you, but when you aren’t allowed to write in the way you talk, it’s like using the wrong end of the shovel to pick up, for example, a turd.
Over time, I noticed something unexpected and wonderful was happening with the blog. I had an army of volunteer editors, and they never slept. The readers were changing the course of my writing in real time. I would post my thoughts on a topic, and the masses told me what they thought of the day’s offering without holding anything back. Often they’d correct my grammar or facts and I’d fix it in minutes. They were in turns brutal and encouraging. They wanted more posts on some topics and less of others. It was like the old marketing saying, “Your customers tell you what business you’re in.”