And I mean that in two entirely different ways. Last week I attended the Social Gaming Summit, the latest event to focus on a growing sector of the game industry. The term “social games” is actually a slight misnomer — referring to games built on social networks (eg: Scrabulous, Parking Wars), rather than those played in person amongst groups of peers (eg: Mafia, Red Light Green Light). But for the 400 publishers, developers, and investors gathered in San Francisco last Friday, social gaming meant very large user bases, and the potential for big, big returns.

So yes, social games are big, in the sense that it’s a brand new market a lot of people are excited about right now. But they’re also big in another way. I’ve mentioned before that Facebook is a unique platform for game design, but neglected to mention its biggest feature: size.

If you’re designing a deep social game, you need to think about scalability on an entirely new scale. This isn’t “five to ten players”; this is “five to ten thousand” (or if you’re lucky, many more than that). Infrastructure aside, the design itself can’t buckle under the weight of unexpected growth, or wilt when too few are playing.

I’ll talk more about scaling for design in a later post. Needless to say, I’ve taken a keen interest in the social gaming space. Interacting with the APIs of social networking applications can yield tremendously potent results, and the relaxed, asynchronous nature of such sites lends itself to tabletop adaptations and casual games — which just happen to be my strong suits. I think I’m going to like it here.

Industry veteran Brenda Brathwaite has taken a keen interest in Facebook, and its role as a nascent platform for game development. Because of the social network built into the site, and the ability for any app to tap into that network, Facebook is most definitely not familiar territory in terms of game design, something which only a few developers have realized as of yet.

As I see it, games on Facebook exist in three distinct categories, which I’m calling “flat”, “shallow”, and “deep”. These terms describe the degree to which each game takes advantage of the Facebook social network, and do not reflect the quality of each game.

Flat games exist on Facebook, but they might as well exist anywhere else. They’re almost always single-player, and do not involve the available social network through the gameplay. (I want to stress “through the gameplay,” as many of these apps do take advantage of the network to create leaderboards and share high-scores, but this does not affect how the core game operates). Examples are popular apps like Jetman, Tower Bloxx, and the copious arcade compilation apps that let users play classics like Snake and Tetris. Sometimes, these apps are simply Flash applications ported to Facebook.

Shallow games do utilize the social network in gameplay, but usually to a fairly limited degree. Examples of this include Texas Hold-Em Poker, and the ever-so-excellent Scrabulous application, both of which use your friend list to organize potential opponents. Scrabulous was the first app I encountered that made smart use of Facebook, turning Scrabble into a divine play-by-mail-esque experience. Still, the gameplay is largely unaffected by the network.

Finally, deep games take more direct advantage of Facebook’s features, building core mechanics around social networks, and using additional methods to incorporate the whole of Facebook into the gameplay. The best example of this is the Werewolves/Vampires/Zombies application(s) which took the gameplay onto Facebook’s walls and PMs, as players lured unsuspecting friends in order to increase their power. A more recent addition to the deep end is area/code’s Parking Wars, which has users leaving cars on the streets of their friends in a strange parking-oriented version of “chicken.” Both games re-imagined the social network as something else (be it food or free parking), and built gameplay around this fiction.

Both games also offer incentives for inviting more friends to play, which contributes to their fast-growing popularity. Brenda goes more in-depth on the dark-side of Facebook propagation, but I would certainly be interested in exploring non-invasive means of designing deep Facebook games. Expect at least one more post on this topic.