From time to time, the Web standards community unburies proposals made long - and sometimes very long - ago. That's currently the case with the excellent <a onlyreplace> thread on the WHAT-WG mailing-list. Although still unpolished, the proposal does make sense and is not logically very different from the overlays XUL authors use on a daily basis.

Here's my own take on the <a onlyreplace> proposal.