“Above the fold” is a common term used to explain position of elements like image, advertisement etc on websites. It is the visible browsing area of a website that can be seen by users without having to scroll webpage. Google Labs online tool “Browser Size” allows you to see similar visible browsing area of any website in analytic manner.
It also show percentage level of users likely to see specific area without having to scroll webpage. Just enter any website URL at the top and click GO button. You can also click on different opacity bars to change the visible display of webpage and overlapping percentage statistics. Interesting web tool, try Browser Size.