Google Browser Size is a visualization of browser window sizes for people who visit Google. For example, the “90%” contour means that 90% of people visiting Google have their browser window open to at least this size or larger. This is useful for ensuring that important parts of a page’s user interface are visible by a wide audience. On the example page that you see when you first visit this site, there is a “donate now” button which falls within the 80% contour, meaning that 20% of users cannot see this button when they first visit the page. 20% is a significant number; knowing this fact would encourage the designer to move the button much higher in the page so it can be seen without scrolling.”
Google Browser Size is an excellent resource. I will come back often. Now, Google, let’s make it look nicer!
(thank you john!)