At first, blogging and screencasting was a bit scary for me. I have been privately and publicly writing and recording myself frequently just to get the hang of it.
Screencasts are great for explaining and showing off your work. Both for marketing purposes but also for motivating your team and showing off complex workflows if words just don't cut it.
I think for every programmer that finding ways to show and explain yourself in other ways than to just code can really improve your personal and professional life.