Why blog? Because you want to...

Promote yourself. Capture and sell your knowledge. Improve your writing. Increase your professional appeal when networking. Impress your boss. Impress your friends. Become more visible in the job market. Position yourself as an expert. Increase your chances of getting a job (or a promotion). Better serve your clients by sharing your knowledge. Differentiate from your competitors. Impress women. Impress men. Impress your in-laws. Show off a little (with subtlety and grace, of course). Benefit (finally) from the Internet. Partner with other expert bloggers. Make more money as a consultant. Motivate yourself to read more in order to write more. Become more respected, more fulfilled and more confident.