[Editor's note: Earlier today, we reported that social gaming company Playdom is making $50 million in annualized revenue through virtual goods. Marketing and gaming veteran Eric von Coelln responded, wondering how the company could be making this much based on the current size and engagement level of its user base. Here's his analysis.]

I had a hard time grasping Playdom’s revenue when I knew Zynga is reportedly making $200 million with nearly five times the audience on Facebook — and has games that are nearly 2 times “stickier” than those created by Playdom.

The Stickiness Factor as a Proxy for Revenue Potential

To generate revenue from users, a game has to be sticky: compelling enough to get a user to come back day after day and engaged enough to want to open their wallet. So while Monthly Active Users (MAU) tells you the reach of your application, taking the Daily Active User number (which ISG has access to) divided by the MAU tells you how sticky the application is. Based on that measure Zynga’s applications are 93% stickier than those developed by Playdom:

• Playdom on Facebook: 1.78m DAU/28.0 m MAU = 14.8%
• Zynga on Facebook: 36.4m DAU/127.7 m MAU = 28.5%

But Facebook is only part of the picture: Playdom has long been the leader on MySpace (with a higher installed base than Zynga). In addition, developers have often stated MySpace has nearly twice the payout per user compared to Facebook (because 63% of MySpace users come from the US according to Alexa and 30% of Facebook according to their reporting).

Comparing Apples and Oranges

To get the whole picture, we need to make a couple assumptions: 1) the majority of revenues for both companies are coming mainly from Facebook and MySpace and 2) the majority of revenues are coming from the US and 3) we need to compare the MySpace and Facebook users based on MAUs in the US.

Unfortunately, MySpace doesn’t report MAUs, only total lifetime installs. In my experience with MMO PowerSoccer.com, users-to-installs would be in the 30% range, but in the social games space, I’d guess around 50% of those that have ever installed can still be counted as coming back each month to play.

Looking at the Top 25 games on MySpace, Playdom has 51.9 million installs vs. Zynga’s 39.2 million. Let’s convert that to Monthly Active Users based on the assumptions above:

• Playdom MySpace US MAU = 51.9 million installs * 63% US * 50% installs active = 16.4 MAU
• Zynga MySpace US MAU = 39.2 million installs * 63% US * 50% installs active = 12.4 MAU

Now let’s add in Facebook’s US Monthly Average Users, pulled from AppData and filtered for the US:

• Playdom Facebook US MAU = 12.0 MAU * 30% US = 3.6 MAU
• Zynga Facebook US MAU = 127.7 MAU * 30% US = 38.3 MAU

Comparing Revenue per Monthly Active User

Now we have a better comparison of US MAU for both companies: Playdom with 20 million and Zynga with 50.7 million. With the stated revenue of $50 million for Playdom and $200 million for Zynga, that shows that Zynga is making 57% more per US MAU than Playdom:

• Playdom Revenue per MAU US = $50 million / 20.0 MAU US / 12 mos = $0.208
• Zynga Revenue per MAU US = $200 million / 50.7 MAU US/ 12 mos = $0.328

While this isn’t precise — as we’ve made a great deal of assumptions — it does go a long way to validating the $50 million mark for Playdom in that it captures the value of Playdom’s sizable MySpace audience while preserving the revenue per user premium Zynga attains from having stickier games.

In addition, I think this allows both analysts and developers new ways to better benchmark their performance, both in game stickiness and in comparing MySpace and Facebook audiences.

Eric von Coelln was the vice president of marketing at Oberon Media, a leading multi-platform casual games company, and most recently the vice president of Marketing at PowerSoccer.com. He now is a New York based free-lance consultant to games, e-commerce and social media companies, and blogs here.