Watched pages and entry highlighting
When you add a page to your list of watched pages changes to that page will be highlighted in Recent Changes. Adding a page is done by selecting the toggle watch option at the bottom of the page. This helps in tracking pages. By default pages are added as category 1. You can also set the category to 2 or 3. The default values are:
You can change the default highlighting behaviour (not the colors) in User Preferences.