Hehe, got this Sunday on a Stratholme raid. Out of like 20 people rolling on it, against two 95s, then a 99 roll, I rolled a 100. http://www.thottbot.com/?i=13652
The radius is not that large (heard it was huge in beta) but it reaches most people standing around an auctioneer stand.
I think its the first one found on my server, so a lot of the reactions are priceless. I also found it humerous how people see a large number of people dancing at an auctioneer and just run up and (on their own) start dancing as well.