Here is some fun NPD data to chew on for a second.  Take a look at the Top 10 PC games of 2007 and compare then to the top ten console games in the list below.  Take a look and see what you think.

Top 10 PC Games of 2007

 1. World of Warcraft: Burning Crusade*– 2.25m
 2. World of Warcraft* – 914K
 3. The Sims 2* – 534K
 4. The Sims 2 Seasons Expansion Pack– 433K
 5. Call of Duty 4: Modern Warfare* – 383K
 6. Command & Conquer 3: Tiberium Wars* – 350K
 7. MS Age of Empires III* – 313K
 8. Sim City 4* - 294K
 9. MS Flight Simulator X* - 280K
10. The Sims 2 Bon Voyage Expansion Pack –  272K

Top 10 Console Games of 2007

  1. Halo 3 (Xbox 360) -- 4.82m
  2. Wii Play w/ Remote (Wii) -- 4.12m
  3. Call of Duty 4: Modern Warfare (Xbox 360) -- 3.04m
  4. Guitar Hero III: Legends of Rock (PS2) -- 2.72m
  5. Super Mario Galaxy (Wii) -- 2.52m
  6. Pokémon Diamond (DS) -- 2.48m
  7. Madden NFL 08 (PS2) -- 1.90m
  8. Guitar Hero II (PS2) -- 1.89m
  9. Assassin's Creed (Xbox 360) -- 1.87m
10. Mario Party 8 (Wii) -- 1.82m

So what are the differences?  Notice how mush fewer sales the PC titles got?  Is the PC market shrinking as the console market to booming?  Well actually the problem here is piracy.  So many people are using pirated games that is it killing the PC market.

The makers of Call of Duty 4 where shocked to see so many people online playing their game with a stolen copy. To me this is stupid since the game makers can trace your IP address but it also shows the arrogance of the thieves.

This is the flaw of the PC marketplace and why you now see developers like Infinity Ward and Epic are focusing their efforts on console gaming.  The PC market has been bad for a long time but now game consoles that can compete with PCs for graphics and horsepower.  There is no need to support the PC which is what several developers have started to do. 

Source:
COD4 Piracy Article