1. I enjoy sharing things with the world. 2. I got to know a lot of people who wrote me mails because I posted something. Some really nice connections with people from all over the world. 3. I learned a new programming language by developing my own blog software. 4. In job interviews I can tell about developing my own blog software with new technologies.
But I just post when I want to and what I want to. That can range from tutorials to just a casual images I took when walking through my neighborhood.