commit: 6b2ca8a - #414 (2014-03-05 12:54:44 -0500)
Doing the site:digg.com search myself, it looks like they did.
Matt Cutts just clarified via his Twitter that it was an "accident".
Whoops:) Maybe they forgot to uncheck the "de-index entire site" box.
it think it was all about the lolz, with Digg announcement it's releasing a Google Reader replacement. at least that's what i prefer to believe.