A dummy edit is a slight change in an article's wikitext that has no effect on the rendered page but allows you to save a useful edit summary. This is like a SMS (Short Message Service).
To make a "dummy edit" just make a slight non-rendering change to the page, fill out the edit summary with your short message including this tag: [[WP:dummy edit]] (include the four square brackets), and save your change. (Note that a null edit does not modify the wikitext and does not allow you to leave an edit summary.)
