Diablo III May 1st Announcement

I would imagine it's easier for them to operate solely with each individual game. As you've got to figure Worldofwarcraft.com probably gets a shit load of traffic, and if you were to combine it with diablo2, and starcraft as well as whatever other crap Blizzard floats around you'd have a server cluster fuck and plenty of downtime. If they individualize each game to meet the certain needs and bandwidth usage they don't have to worry about a clusterfuck, that's why.

Agreed. As it is World of Warcraft is often times laggy if not inoperable when there is any sort of server shut down. It's obvious they could do them all from the same site but it'd be more tedious for the consumer.