This question has been raised by the appearance of WebLogs in wikis (and earlier, RecentChanges when that was first introduced). But those didn't require a complete solution re time. To get calendar/datebook features of WikiAsPim though we really need to figure something out, and it would probably be nice if there were an integrated way that wiki dealt with time wherever it came up.
A page for every day? And then a way to include information from many days' pages on one page?
What's the wikiest way to do this?
See also ArchivingNews, TimeStamp, TemporalContext.
The key difficulty in current wikis is due to every unique page requiring a unique page name, one which is reasonably sensible text and not some autocreated mumble.
However, if each chunk of text existed without a name, only a date, you could then assign one or more wiki names to each of those chunks (in a manner similar to assigning categories), and then the wiki page itself transcludes all those chunks together in one view.
It's a pain though - each chunk if it continues to exist as a discrete chunk means that all the chunks have borders ... unlike this wikipage of text where one paragraph above flows into the next, and you'd be hard put identifying where the day breaks are. The WikiNow is not just the timelessness of a page, but also the blurring of borders between the chunks of contributed text.