Gaming social network Raptr has released a study that shows just how hardcore Zynga gamers can be. Based on the report, gamers who play the likes of CityVille and Adventure World play online almost as much as those who play Halo.

The report looks at the amount of time that Raptr’s 10 million users played online, and which games they were playing. Call of Duty, unsurprisingly, was the most popular with a 43 percent share amongst the top gaming franchises. World of Warcraft was next with 17 percent, then Halo at 14 percent, followed very closely by Zynga’s line-up of “Ville” games at 13 percent. And Zynga’s games actually outperformed other notable game brands like Assassin’s Creed and Gears of War, when it comes to time played online.

Other interesting statistics:

  • Zynga fans play games up to eight times a day, four times more than games like WoW and CoD, though these play session are much shorter.
  • Zynga games accounted for 75 percent of the online playtime amongst Raptr users since 2008, with EA/Popcap coming in at a distant second with 10 percent.
  • Zynga players are very loyal. 90 percent of the audience for games like FrontierVille, CityVille, and Empires & Allies consisted of existing Zynga players who played previous games from the developer.
  • Though the average playtimes are relatively short for Zynga games, since the release of YoVille back in 2008 the length has doubled, and now sits at around seven minutes per session.

The study not only shows that many Zynga players are pretty hardcore, but also that hardcore gamers are starting to play Zynga games. Amongst the players of some of the biggest PC games, including StarCraft 2, World of Warcraft, and Call of Duty: Black Ops, between 12 and 20 percent had played CityVille. Likewise, 30 percent of Xbox 360 gamers also play Zynga games.

“Zynga has had an undeniable impact on the gaming landscape,” Raptr CEO Dennis Fong said. “However, little is known about the behavior of Zynga’s players. By looking at the actual gameplay habits of real users, we’re able to get a deeper understanding of how Zynga has been able to dominate the social gaming space and command one of the highest projected IPO valuations this decade.”

You can find the entire report here (PDF link).