Real-time strategy games are mainly made for PC because they are played using the mouse. There are some non-PC RTS games as well, but those games are often not as popular.
Popular RTS games include Warcraft 3, Command and Conquer, Red Alert, and Starcraft. There is a big buzz around these games, especially Warcraft when people hook up via the Internet to play multiplayer modes. Some live and die Warcraft. They spend hours in front of their PC's and it is like their whole life revolves around the game. That is right. No work, no excercise, no sleep... just the "virtual" social life. Just imagine how successful RTS games are...