Most of your IDEs, audio, image, and video software is setup by default for wide screen viewing with tool bars to the left and right of what you are working on, even pdf has a table of content on the left hand side by default for navigation when sifting through large amounts of documentation.
So if you don't have multiple screens then it's probably not something that will benefit you.
As for their web page example of google the right hand side of the page will have other information in it that doesn't appear in a generic search like freebase, imdb information, or advertising depending what you search for. Google is about the only place where I click on advertising since if I'm looking for a replacement part and I google a part number.. the ads are places I can purchase the item sometimes even locally which is what I was looking for in the first place.