A recent report by Lou Kerner analyzing Facebook traffic across all the major social game publishers’ games shows that almost every social games company experienced losses in traffic for the month of May… all except Playdom. The catalyst for the loss of users was undoubtedly Facebook’s decisions to turn off two key viral Facebook features: notifications and requests. Are we about to see a shake up in the leadership of social gaming, and will Playdom begin to encroach on Zynga’s turf?

The report comes from SecondShares co-founder Lou Kerner, and lists the top losers for the month. The report is not pretty. Zynga lost 10% of their userbase, Electronic Arts-Playfish lost 11% and CrowdStar lost 12%. This means that these companies were heavily reliant on players who were coming back by clicking on notifications in the notifications feed and requests to play the game. Now that these activities are gone, some of those players just didn’t return. This really underscores the fact that our current standard measurement tool of the popularity of these games don’t really capture how much the players are actually engaging or liking the game. We see analysts and companies parading numbers like Zynga’s 230 million monthly active users, but when that falls off by 26.6 million users in a month, we realize that many social gaming company valuations hinge on the continued growth of these companies at the same rate that they’ve been growing to date.

The big story in the report is that Playdom, on the strength of its excellent Bola soccer game, was able to completely buck the trend and grow by 1%. This corroborates anecdotal evidence of the company’s recent moves. They’ve been acquiring top quality developers (including Three Melons, the creators of Bola), Acclaim Games and Offbeat Creations and introducing hit games like Social City. Their existing catalog, including Wild Ones, displays an eagerness to bring a wider variety of gameplay mechanics to Facebook. Their CFO Christa Quarles’ discussion of social games at the Social Gaming Summit was extremely impressive. Will they be able to continue their growth? Let us know what you think in the comments.