Along with its list of the most-played consoles in 2008, research group The Nielsen Company has provided its list of the past year's most popular PC games in the US.

Of the ten titles, none were released in 2008, and only 2 debuted in 2007. The list is based off data from January through October 2008, meaning that the impact of the second World of Warcraft expansion, Wrath of the Lich King, was not taken into account.

Unsurprisingly, Blizzard's World of Warcraft topped the PC charts, with those surveyed playing the PC MMO an average of 671 minutes, just a bit over 11 hours, per week. Blizzard's Diablo II also appears on the list, as do three games from Valve.

Unfortunately, Nielsen did not specify the methodology behind this year's results. In 2007, the firm based its list off an extremely small pool of participants, a mere 1200 gamers, which could explain the unexpected results. It is not known if this was changed for 2008.

Top 10 PC Game Titles in the U.S.
1. World of Warcraft (2004) / Blizzard Entertainment
   671 Avg Minutes Played Per Week / 0.723% AU*
2. Call of Duty 4: Modern Warfare (2007) / Infinity Ward
   403 Avg Minutes Played Per Week / 0.163% AU*
3. Halo: Combat Evolved (2003) / Gearbox, Bungie
   295 Avg Minutes Played Per Week / 0.092% AU*
4. The Sims (2000) / EA Maxis
   213 Avg Minutes Played Per Week / 0.09% AU*
5. The Sims 2 (2004) / EA Maxis
   291 Avg Minutes Played Per Week / 0.086% AU*
6. RuneScape (2001) / Jagex Ltd.
   451 Avg Minutes Played Per Week / 0.084% AU*
7. Diablo II (2000) / Blizzard Entertainment
   313 Avg Minutes Played Per Week / 0.065% AU*
8. Team Fortress 2 (2007) / Valve
   371 Avg Minutes Played Per Week / 0.063% AU*
9. Counter-Strike (2000) / Valve
   282 Avg Minutes Played Per Week / 0.062% AU*
10. Counter-Strike: Source (2004) / Valve
    426 Avg Minutes Played Per Week / 0.061% AU*
*AU is the percent of PC Gamers playing title in the average minute.
Data from Jan - Oct 2008.

Upon the debut of its GamePlay Metrics tracking in 2007, Nielsen explained its methodology as it appears below. It is not known how or if that changed in 2008.

Nielsen GamePlay Metrics Methodologies as of 2007

Nielsen GamePlay Metrics uses console data collected from the Nielsen's People Meter TV sample combined with Nielsen GamePlay Metrics' proprietary audio signature library that matches the unique audio signature of every game tracked on the six most widely available video game consoles, including PlayStation 2, PLAYSTATION 3, Xbox, Xbox 360, Wii and GameCube.

The GamePlay
Metrics user sample includes more than 12,000 households with approximately 33,000 individuals.

Nielsen GamePlay Metrics uses PC data collected from the Nielsen's Video Game Tracking Survey. Video Game Tracking is a weekly online survey of 1200 gamers 7 - 54 years of age. Qualifications include ownership of a console or PC, play video games at least 1 hour per week and have purchased at least one or more video games in the last 6 months. The Video Game Tracking online survey has been in the field for more than two years (104+ weeks).

Additional data, including rankings of console video game titles and the electronic metering of PC game titles are in testing and will be available to select Nielsen GamePlay Metrics clients in the near future [as of 2007].