Obama won because of Internet popularity and he utilize the online way of reaching voters.. I think that answers your question how powerful internet is..
The Internet obviously enables a company to advertise and sell its products and services. For advertising, think banner ads (very reminiscent of print ads, by the way). Obviously, you can also buy things online, Amazon and others come to mind. But that is not all. InternetAd.biz
I think, in the modern society, few companies could afford to go without proper online strategy. Branding and being on top of search engines are actually tied up these days.