When people think about online social gaming, two broad categories of games immediately spring to mind: casual social games and hardcore MMOs. Despite the criticisms leveled by traditional game designers at casual games for their Skinner Box-like appeals to our core psychic compulsions, these games have become wildly popular on Facebook and mobile devices. MMOs, while never as broadly appealing, enjoy multi-year runs and rabidly loyal user bases. One common contributor to the success of both types of games is their unique social mechanics, which might be summarized as follows:

Casual social games:

• Inviting "neighbors," sending gifts, visiting your friends' playspaces
• Asynchronous play with asymmetrical, loose-tie relationships

Hardcore MMOs:

• Forming parties and joining guilds, chatting with guild members, coordinating real-time group battles
• Synchronous play with emphasis on symmetrical relationships that build strong ties

As a current designer/producer of hardcore strategy MMOs at Kabam and former designer/producer of casual social games at Zynga, I've become intimately acquainted with both sets of social mechanics. And I find both are very useful in developing sticky, engaging gameplay experiences. Neither is necessarily better than the other.

In fact, as free-to-play (F2P), online, multiplayer experiences make up an increasingly large share of the overall games market, we're seeing titles emerge that mix and match social mechanics from both the casual and hardcore lineages to great effect. League of Legends is a great example of this: Riot's DotA redux came from out of nowhere to make tens of millions of dollars by combining social mechanics from MMORPG PvP battles, RTS duels, and more casual F2P games to create an entirely new genre, the multiplayer online battle arena (MOBA).

Lobby screen in League of Legends.

Much of this evolution of what comprises "social" is being driven by the F2P business model itself. Traditional retail games equate to a single consumer decision: to buy or not to buy. F2P games, on the other hand, feature an ongoing courtship between the player and the developer. Because of the low barrier to entry, players are inherently less committed to any given F2P game. This means developers and publishers must do everything they can to keep players engaged deeply and regularly with their games. This can be done with core gameplay and an effective monetization system; the opportunity cost for leaving a game in which you've invested substantial time and money is high.

But "crowdsourcing" engagement and retention to the players themselves via compelling social features remains one of the surest ways to make a game both sticky and fun. A single-player game is a game, but a social game is a community, with all the fascinating human relationships one expects: competition, collaboration, peer pressure, rebellion, jealousy, compassion, and more. The difference between playing Scrabble against the computer and playing Words with Friends is the difference between killing time and a pop culture phenomenon.

So, for today's F2P online social games, "social" is about the user experience AND about business -- the two are inseparable. Game designers must determine which social mechanics fit their game's target market, gameplay, and business model. Whether these mechanics are traditionally found in casual Facebook games or hardcore MMOs is irrelevant.

Instead of viewing social through this limited, binary lens, this article will analyze player interactions using a set of three general heuristics. The advantage of this approach is that these heuristics can be applied to any online multiplayer game. Freed from a specific game design, their functional value becomes more apparent. Developers can then choose the interactions they feel will best serve their game's design.

Three Heuristics for Categorizing Social Mechanics

Of the three social mechanics we'll examine, one relates to the timing of social interactions and two involve the type of social relationship. Together, these mechanics encapsulate the social interactions of most online games:

• Synchronous vs. Asynchronous player interaction: do interactions occur simultaneously in real time or at different times as in a turn-based game?
• Symmetrical vs. Asymmetrical relationship formation: does forming a relationship require input from both parties or can they be formed unilaterally by a single party?
• Strong Tie vs. Loose Tie relationship evolution: do relationships tend to become deep and long lasting or are they more likely to be light and transitory?

Three heuristics for social game features.

Let's break down each of these heuristics in turn.