I have observed the “blank page” behavior for several days now, enough to make the hypothesis that a work-around to the problem is to bookmark, e.g. http://www.perlmonks.org/index.pl, or to Google and follow the direct “The Monastery Gates” URL ... specifically asking for the content instead of expecting the site to figure out a default.   A preponderance of evidence seems to be growing, in my mind at least, that this serves as a workaround ... and, hence, perhaps a pointer to the underlying root cause.

I am growing more certain that this is a server-side cache related problem that appears to be specific to empty URLs.

HTH ...