I played NetHack for a long time and wanted something more. NetHack becomes pretty repetitious after a while. I tried various roguelikes and hit upon DF. Also,

I played NetHack for a long time and wanted something more. NetHack becomes pretty repetitious after a while. I tried various roguelikes and hit upon DF. Also, I see Dwarf Fortress as the natural progression of programming games. As programmers, we always look to abstract away busywork. DF takes away the busywork of dungeon-building and hands it off to little applets. Basically it became popular by word of mouth. I think the popularity of Minecraft led more people to hear about it, since Minecraft was said to be influenced by it. But as far as I know, it's always been a slow build, never went viral or became an overnight success.