SimCity 4, almost ten years ago. It's still being played today, thanks in part to a Steam launch in 2010, but mostly thanks to the modding scene. However, EA Maxis will not launch the new SimCity in 2013 with mod support.
It's not entirely off the table, though. EA Maxis creative director Ocean Quigley said the ability to support mods is already built into GlassBox, the new engine powering SimCity, so there's potential for mod support down the road -- just not at launch.
"Right now we've got our work cut out for us to build the product up to the quality level it deserves as a SimCity," Quigley said. "Then after we ship, we'll make decisions about how we can and when exactly we'll support mods. But it's worth pointing out that the reason people are still playing SimCity 4 almost ten years later is because the modding community essentially re-created it and filled it with new content and fixed bugs and made it as much of a hobby as it is a game.
"We're very cognizant of that -- we're not idiots."