#9 - Aug. 5, 2010, 10:08 p.m.
The ripples of the Cataclysm will be far-reaching, leaving the face of Azeroth forever changed for all players. So, when we say "[...] changes will be made available to all players regardless of expansion purchase," we simply mean that, even if one does not elect to upgrade their account to World of Warcraft: Cataclysm, he or she will be still able to experience new content—including, but not limited to, the revamped zones of Eastern Kingdoms and Kalimdor. The option to continue playing in "old" Azeroth will not be provided.
Of course, certain content will only be available to those who have purchased the expansion, and we'll be able to share more details on that at a later date. :)