In a recent interview, the creator of Doom and Quake series and legendary game programmer, John Carmack expressed his view that MMO and casual games are what set PC gaming apart from consoles.
"Historically, the real value of PC has been in connectivity, and in modification... but the latest generation of consoles is encroaching on that territory with all the options you've got on current consoles, the connectivity and the add-ons and things you can get there."
"But on the other hand, if you look at what's really successful on the PC - like World Of Warcraft, that's an insanely successful product. It's like a train driving all the PC sales numbers altogether on gaming."
"Just in terms of games that you sit down and play in the console mode, the PC probably doesn't have a huge amount of differentiation, and that's unlikely to change."
"But the different areas where the PC is still standing on its own is MMOs, and a lot of casual games are interesting, too. The people that sit down to play games are predominantly playing them on consoles -- at least, higher-end games -- but the PC still has a strong enough margin to make games, and we continue to support it."