In the new piece, Kelly shows how the game casually but constantly prompts the user with questions and suggestions to smooth the process of sharing gifts and bonuses with friends, through channels such as wall posts, in-game notifications and e-mail. This sharing is key to spreading the game around players' social networks, Kelly shows.
But Kelly also looks at how CityVille's idea of player-to-player interaction is really guided more by selfish self-interest than any real camaraderie between players.
"Itís all incentive-driven," he writes. "One of the ironies around social games is that they arenít particularly social. ... Social games are not trying to be connections or meaningful experiences for players. ... Instead, they are built as amusements. Socialising in amusements is more akin to having spare Poker chips at the table that you give to someone else, and maybe theyíll give you some back later. It is reciprocal trade, assistance for incentive, not charity."
Kelly also analyzes of the economics of CityVille, both within the game and in the real world for publisher Zynga. He argues that, by selling hard-to-find in-game cash in transactions up to $99, Zynga is engaging in a clever psychological trick that makes cheaper options look comparatively better.
"In all likelihood, very few players actually buy that $99 pack," he writes. "Pricing psychology often works in such a way that a very highly priced item helps to set the tone for the value of all other items (in consumersí minds), leading them to choose the mid-range item."
The fine-grained look at CityVille concludes with a look at what other social game developers can learn from CityVille's success, arguing somewhat depressingly that smaller developers can hardly hope to beat Zynga at its own game at this point.
"Zynga are in a position similar to Facebook and Google, where they have become such a dominant incumbent with so many invested users that they have created a buffer around themselves," he writes. "Hearing a social game company talk about how they are going to spend $300k on development, making their own cheap knock-off games, and then become The Next Zynga is like listening to small startups convincing themselves that they just need to make a better search engine to take down Google."
The full feature also includes Kelly's suggestions for some ways Zynga could improve the CityVille's experience, including an overhaul of the energy mechanic and a severing of the connection between social embarrassment and in-game payment.