Each classical wiki could be handled this way, but it costs a lot of discipline to always stay within the frame of one slide. So the author suggests to handle a Slide Wiki in form of a TwinWiki pair (V,W), where the slides reside in V and the overspilling part is saved in W. V is always in DocumentMode, while W is a repository for the rest.
Since ThreadMode would break the slides in "no time", we have the following options to avoid this: