They did? When? Really, I want to know.

Are you sure? I thought it meant that people who had attained a 310% mount could learn the ability across all mounts to stop them being restricted to using one or two. I didn't get the feeling that it was open season for all - if it is I expect it to be priced very high indeed, and I hope free or minimum cos to those already with a 310% flyer.

@Ian -- it's what you say. You get the 310 ability, it'll apply across to all your flyers so you can keep using all your mounts. I haven't seen anything implying that 310 would be purchasable.

This was in the last developer twitter chat (on april 16):

"Q: Do you intend to have all 280% flying mounts scale to 310% when a 310% mount is earned, or will only purchased mounts do so?

A: Our current plan, is that in Cataclysm, you can learn a new rank of flying that lets all flying mounts move at 310% (even current 280% mounts). That will probably be as fast as mounts will ever get. We don't like it that when you get a 310% mount that you stop using your old ones. "

"learn a new rank of flying" seems to imply that it will be purchasable by everyone. But it's a little open to interpretation.