I'm always looking for context when I read things; the date is most often a very important context.

Consequently, I hate it when a website serves up a page that has no dates at all, anywhere AND the server gives the "Last-Modified:" header as /right/ now..... Dates are very important and I very much appreciate having them in both the URL and the content; sometimes the time of day is important too, but usually only if it is quite recent.