EditSummary

When you edit a page, there is a small box with the words "Summary" under the main edit-box. It looks like this:

The location of the Summary box on an AboutUs edit page is shown in the picture on the right, circled in red.

You can write up to 200 characters there. These words will show up on the Recent changes page, in the page revision history, and in the watchlists of users who are watching that article.

It's always good to write something in the Summary, or add to it in the case of section editing. This lets people know what you changed. You can also say why you made the edit.

Providing an edit summary, even if the edit is minor, makes AboutUs work better by quickly explaining to other users what your change was about.

It's also a good idea to set your user preferences (under Edit) to "Prompt me when entering a blank edit summary".

For more information, see http://meta.wikimedia.org/wiki/MediaWiki_User%27s_Guide:_Edit_summary