Don't worry, though. These realm closures have nothing to do with any dips in WoW's popularity. It's actually due to the launch of WoW's Russian localization. A vast majority of the players on those particular realms were Russian players, and they migrated to the new Russian servers when they opened up, leaving most everyone else high and dry. The equipment these four servers run off of will likely just be used elsewhere, since Vaneras stated they'll be prepped for Wrath of the Lich King's launch after being taken down. Most likely they'll need to launch a few more realms when Wrath rolls around, but it was just far easier to fold these four into larger communities at this point.
[ Thanks, Swarfy! ]