100% of my online income comes from mainstream non-adult these days. 2 years ago I cashed out, sold off my traffic sites, paysites, etc and timed it pretty good by fluke heh.
I've also got offline businesses which keep me busy (consulting and running an expat food cafe in china).
I don't know about usa, but back when I was living in Australia if you turned a bedroom into an office, you could also claim as a business expense the power/gas to that room on a % base. Which was a nice extra thing to lower your tax liability.
-N