Hello,
As said above a lot of people float the ground. It prevents noise from ground loop hum especially on single ended equipment. Also, by having the ground plug only connected to the wall and not the component provides some type of RFI/ EMI protection. I bought a Nordost Purple Flare figure 8 power cord for my BlueSound Node 2i. I bought a cheater that turns a three prong EIc into a figure 8. I then plugged in my Nordost Blue Heaven which is grounded. Their was a definite improvement over the sound. At a Nordost/ Ayre/ Kef show at my local audio store I asked the Nordost rep about it. He said the cables are the same except for the ground wire and the figure 8 end. I tried it several times and had the sam sound improvement each time. I think Paul at PS Audio has talked about only connecting the ground or shield cable on the starting side. The interesting thing is the ungrounded Nordost Purple Flare still uses a three prong plug on the wall side even though their is no ground wire in the sheath. So not using the ground but using it as a shield.