Diff-IE is a prototype Internet Explorer Add-on that will help you find the changes to any webpage since the last time you visited it or opened it using Internet Explorer. It also allows you to view and compare previously cached versions of a page. Diff-IE add-on requires Windows XP, Vista, or Windows 7, and Internet Explorer 7, 8, or 9 beta. The add-on shows the count of visits to any page and also highlight the changes happened since you last visited.
Once installed, it adds a toolbar from where you can compare the versions. You need to enable cookies on your browser to use this feature.
The add-on has few settings available where you can select the sites to ignore, change the highlighting color etc.