What does it mean to roll a golf green?

I was reading this article and came across a term I was unfamiliar with. Would anyone care to enlighten me?

USGA officials said Saturday that the green was inadvertently rolled before Saturday’s round. “I found out after play was completed today that, for some reason, a different person on the grounds staff rolled that green today, despite the orders that we had given not to roll the green,” Driver said.

from http://sports.espn.go.com/golf/usopen04/news/story?id=1825166

Kind of like it sounds. A weighted drum is rolled over the surface of the green to compress it and make it harder, and therefore faster.

Yep, here is an example of a greens roller.

I think… I think it means they worked it over and moved the hole. But I am FAR from sure.

Wow, it’s been a while since I rolled a green. Look 'a that fancy machine.

Yeah, the course superintendent at Carnoutstie once said:

“The players have titanium and psychologists. All I have is nature.”

Well, to be fair, you have nature plus 600 lb. instruments of tourture like that one.

Gosh, with all of those specs, I almost expected to see jump jets and a PPC listed, too!