Wow, have you seen Google Browser Size? The Google Lab powered site demonstrates with a very neat overlay the percentage of users who can view your website past certain resolutions. Check out this screenshot:
As Google Browser Size demonstrates, only 50% of computer users will be able to see a full layout that is 1050px in width or more without having to scroll horizontally. And that prominent “Donate” button located towards the bottom of the page? Only 30% of computer users can see it without having to scroll. You can check any URL using Google Browser Size – perfect for when you’re tweaking layouts and you’re not quite sure if you’re making it too big or too small!