User blog comment:Ohmyn0/Making your wiki HTML5 compliant/@comment-5473581-20120707015321/@comment-2200849-20120707090244

The s tag is designed to mark text that is no longer correct, while the del tag defines deleted text. Both provide strikethrough by default, but you can style them with CSS to look as you wish. That is one of the greatest advantages of separating HTML markup from styling.