We discovered a little while back that Wrath was going to ship on DVD in both the collector's edition and the regular edition. This is great news for anyone with a DVD drive in their computer, because swapping discs is annoying. However, I'm sure there are still a few people playing WoW that don't have DVD drives; its system requirements are, after all, very forgiving. We haven't had any solid information thus far on whether the expansion will ship or be available on CD as well, like the BC collector's edition.
It turns out the answer to that is no; Vaneras states quite clearly that WotLK will "only be available on DVDs, not CDs," for both the regular and the collector's edition. This implies that those of you who don't have DVD drives may well be out of luck on launch day. I say "on launch day" because I'm assuming the expansion will be available for digital download eventually, as both classic WoW and BC are. However, it may not happen right away; the digital download for BC didn't become available until about two weeks after launch.
Now I'm curious: how many of you are going to be affected by this?