On the forums, poster Alorn asks when we're going to see a preview of the next expansion -- since, after all, Blizzard has told us that they're planning on having yearly expansions. Next January is only 10 months away, and we had previews of the Burning Crusade well in advance of 10 months to release. To this question Nethaera replies that Blizzard has not claimed they'll be producing yearly expansions -- but instead that they "wanted to try" to release an expansion a year. This sounds a bit different from what Blizzard COO Paul Sams told GamesIndusrtry.biz back in August, when he said:
Starting with The Burning Crusade, every year thereafter we plan on bringing out a new expansion set - so every 12 months.
Though I suppose "we plan" is different from "we will," and we can go back to Blizzard's usual "when it's ready" release date strategy.