For years, Blizzard Entertainment's World of Warcraft has been the most popular Massively Multiplayer Online Role Playing Game and every new MMO that hits the scene is inevitably compared to it. As of today it's an unkillable giant in the video game business's newest category. But why WoW? How is it that mostly no-frills Real-Time Strategy franchise evolved into the premiere online gaming experience?

Looking back at the development history of various Blizzard products, not just those in the Warcraft brand, it's easy to see the building blocks for WoW. Back in 1994 when Blizzard released the original Warcraft: Orcs and Humans, online gaming wasn't even a glimmer in the company's eye. Warcraft: Orcs and Humans was just one of several fairly successful Blizzard titles and it didn't do anything particularly innovative with the RTS genre. Arguably Crio/Virgin Interactive's Dune was a more complex strategy game and only a year later in 1995 Sierra's Command and Conquer would provide more variety than Warcraft, which was really just one mechanic with two different skins.

It wasn't until after the release of Warcraft II: Tides of Darkness that the series first touched the shores of online gaming. Blizzard launched its pioneering online multiplayer platform Battle.net in 1997 just a few months after Tides of Darkness and its expansion Beyond the Dark Portal hit shelves. Battle.net streamlined the Internet-based multiplayer process at a time when Internet connections were still fairly slow and unstable. Ironically, Battle.net wasn't originally designed with Warcraft in mind. Rather, it was a platform intended mostly for Blizzard's highly anticipated action RPG Diablo. While Diablo and its sequel had a strong online presence, Blizzard's biggest Battle.net successes were in the RTS genre.

Once again, Warcraft wasn't the franchise that initially spurred Blizzard's attention to Battle.net. It was the spiritual successor to Warcraft, the science fiction RTS StarCraft that became the Battle.net star. Battle.net usage increased by tens of thousands of users with the release of StarCraft and its expansion Brood Wars. This required Blizzard to maintain an online multiplayer system that could support a truly massive number of players and to create some of the first account protection systems, such as CD keys. Other innovations, like session-specific filters, were implemented for the large StarCraft community.

But all of these things are just the technical components on which WoW is based. It wasn't until Warcraft III: Reign of Chaos that Blizzard found the missing piece of the puzzle. Reign of Chaos and its expansion Frozen Throne augmented the traditional RTS experience with the addition of Hero units, special characters that were more complex and important than the replaceable soldier units. With unique abilities and more detailed designs, these Hero units are like prototypes of the avatars controlled by players in WoW. By combining this new paradigm in RTS gameplay with the robust online play technology developed over years with Battle.net, Blizzard was poised to reinvent the MMO so drastically that its concepts would become the gold standard.