Blizzard Entertainment, the creator of real-time strategy games like Warcraft III and Starcraft II : Wings of Liberty, is working on a marketplace for custom maps — much like an App Store for its games — to provide some incentive for users that make new game modes and maps, said Chris Sigaty (pictured on the right), Starcraft II’s lead producer at Blizzard.

Players can use the Warcraft III and Starcraft II engines to create their own games that could be drastically different from the original versions of the real-time strategy games. Blizzard demonstrated that by creating a game like Popcap’s Bejeweled game, called Starjeweled, within the Starcraft II engine.

But discovery can be a problem, as can having an incentive to create good custom maps — so Blizzard wants to give designers a way to earn money off their maps, Sigaty said. Warcraft III is just one example of how custom maps and game modes have greatly increased the longevity of a game, he said.

A custom map for Warcraft III, called Defense of the Ancients (DOTA), has become much more popular than the original game. So much so that Blizzard created its own version of Defense of the Ancients. Blizzard today announced four free custom maps for Starcraft II that will be released in the next few months, including the Bejeweled spinoff and DOTA.

“Custom maps are critical for the longevity of the game,” Sigaty said. “Our long-term goal is to provide users with an incentive to create those custom maps, and have Blizzard-developed maps as well.”

When released, it will be focused on Blizzard’s newest sci-fi real-time strategy game Starcraft II — but there are plans to roll out the service for its future games and also its Warcraft real-time strategy games, he said. But there isn’t a release date for the service just yet, Sigaty said.