This could be Wikipedia's most effective "personal appeal" they've ever run, just for the above reason.

"A true blackout would be hellish: I don't know that there's a day that goes by that I don't read something on Wikipedia (which is the point, of course)."

I think a blackout would highlight just how many people rely on Wikipedia and might bring to light that they wouldn't mind donating a few dollars a year to keep it around.