The Group changes by page in recent changes and watchlist setting in your preferences improves the display of the Special:Recent changes page, by grouping recent changes per day by article, and displaying the titles of the changed articles in order from newest to oldest change. This feature also applies to Related Changes and your watchlist. This only works with browsers that support Javascript (but all of the latest versions of all of the major browsers do).
To activate this setting, do the following:
Click the Preferences link at the top of the page. Then click the Recent changes tab. Then check the box next to Group changes by page in recent changes and watchlist. Then click the Save button.
Note: After saving, you have to bypass your browser's cache to see the changes. Mozilla/Safari: hold down Shift while clicking Reload (or press Ctrl-Shift-R), IE: press Ctrl-F5, Opera/Konqueror: press F5.