A Double Edit is when one edits a page on the wiki, then shortly afterward, from a different ip address, edits it again either making an extremely trivial or even empty change. This causes the "last edited" link at the bottom of each page to display no useful information about the content of the change. This can be either inadvertent as a result of incremental editing behavior or mistakes in using browser history while editing. It can also be used maliciously to add difficulty to the task of identifying and reverting changes to a page.
This phenomenon is largely unique to WardsWiki, as other wiki sites tend to have better versioning interfaces that minimize the effects of Double Edits.