While we're unsure exactly for what, the Public Test Realm character copy function is currently up and running, but not yet active. Could be for the upcoming Echo Isles and Gnomeregan content, could be for the new Ruby Sanctum raid. We have no idea. It may not even mean anything at all.
Of note: my particular character copies haven't been reset since the last PTR testing phase, giving me a grand total of one possible character copy to the PTR servers. You may be in a similar or worse boat.
As always, when Blizzard provides more information about the status of the PTR, as well as its contents, we'll be sure to let you know. Until then, feel free to hammer the character copy server -- you were going to anyway.
Update: MMO-Champion points out that instead of our normal Anasterian and Broxigar realms on the PTR realm list, we have Broxigar and BlizzCon Event. As Boubouille notes: "When was the last time Blizzard needed a server for BlizzCon?"