Essentially, they finally figured out how to win at making games, by using the main strategy Blizzard has been doing for years.
Do it right, and it's not done until it's done.
Now they just need to figure out that by releasing small amounts of information and alpha footage, people will latch on in anticipation. Although we had Warcraft 3 as an intermediary between Starcraft and the upcoming Starcraft 2, it has been
over 10 years since the release of Starcraft. Blizzard clearly knows how to keep interest in an upcoming release, something that ArenaNet must still learn.
Doing
this kind of thing really helps.