According to Wikipedia, a coronal hole is when "a corona (a kind of plasma 'atmosphere' of the Sun) is darker, and colder, and has lower-density plasma than average." And between May 28 and 31, a coronal hole faced Earth and was captured in the above video by NASA.
What effects will the coronal hole's rotation Earth-ward have on those of us living on Earth? Not much, for better or for worse. The solar wind streams that coronal holes can cause generally take two to three days to travel to our planet, so we've likely already experienced the anticlimactic effects of this particular hole.