Is a online business feasible ????

I can design a website with two types of contents - healthcare (covering body systems, general info about drugs etc) and green content (tips, ideas for green living)

But will i get advertisments from businesses to generate revenue ?
Which service should i use - google or yahoo or someother ?
Too many questions unanswered !

need to start own business

i feel a compelling need to start something on my own, but i doubt my capacity and knowledge about it.