If you had wondered why sometimes people fail to find a particular section of your page or website, Browser Size can help you analyze this. This tool from google labs is used by google itself to analyze how people see their website.
The sizes represented in this contour are client area sizes, not browser window sizes. This means they represent the size of the browser without the title bar, toolbars, status bars, etc., and thus give a true representation of how much content can be seen by a particular segment of the Web-using population.
This will give you idea of how to place your content, advertisement and how you can make your content useful for your readers to convert them further. Check out Browser Size