This performance is hardly surprising, given that Zynga's pre-existing network of titles was already hosting over 200m monthly users. As such, luring one third of the player base of CityVille to sample Empires & Allies would be sufficient to provide 30m monthly active users. In terms of debut-month figures, anything less than around 40m MAUs (which Empires is on track to achieve) would be below expectations, given Zynga's capacities for leveraging advertising and cross-Zynga network promotion on Facebook.

We don't expect Empires to match the success of previous release CityVille, however, which pipped 100m MAUs approximately one month after launch. CityVille was a stalwart genre play, iterating one of the most successful emerging categories of games on Facebook in 2010. Empires & Allies , by contrast, is somewhat of a departure, blending slightly more aggressive strategy elements around a resource-management basis. This can be seen as a bulwark against a growing number of games that are attempting to capture a slightly more hardcore base of players - much like Kabam's Dragons of Atlantis or Digital Chocolate's Army Attack - that are seeing increased engagement and retention from slimmer but more dedicated userbases. Although, it's worth nothing that Zynga is no slouch in this regard, with FarmVille especially, given its age, successfully managing to retain the interests of a large audience to an above-average extent.

Zynga's release schedule is slowing, and Empires is the first game from Zynga in over six months, a far cry from its behaviour in late 2009, the period during which it experienced the golden growth that propelled it to the forefront of Facebook gaming. The role of Empires isn't just to gain traction in an upcoming genre and find new audience but also to combat churn: four of Zynga's top ten titles have seen significant loss of foothold in the past quarter, and will need to be replaced or refreshed within an increasingly competitive environment. Even with Empires performing strongly at launch, Zynga is currently 30m MAUs short of the 300m record-high achieved by its portfolio at the beginning of the year.

Zynga's performance during the past quarter, alongside those of other major gaming operators on Facebook, will be the focus of the next edition of our social network gaming Market Monitor, due in July.