Blizzard has plans to connect more World of Warcraft realms, according to a post on the Battle.net forums. Five pairs of servers are due to be linked, though the company doesn't yet "have a specific date on which these connections will occur."
What's a realm connection? It's basically Blizzard-speak for cross-server tech wherein two or more standard realms have been permanently and seamlessly linked. "These linked realms will behave as if they were one cohesive realm, meaning you'll be able to join the same guilds, access a single auction house, run the same raids and dungeons, and join other adventurers to complete quests," the company explained previously.