Researchers at Princeton University recently used epidemiological models to explain user adoption and abandonment of online social networks such as Myspace and have used the findings to predict that in Facebook's case, 80 percent of its user base will be gone by 2015 to 2017.

The modeling is complex, but researchers compared adoption of an online social network as infection and abandonment of said network as recovery. Then they made the model specific by looking at search query data for the online social network Myspace, which used to have millions of users before almost disappearing from the internet.

The researchers argued that most people join online social networks because their friends did, and that same effect works in the opposite direction as well. Spread of ideas has been modeled using what is called the SIR model of the spread of infectious disease.

Myspace, which was purchased by News Corp during its upswing in 2005 but sold at a loss six years later, was a good case to use because it existed almost entirely during the age of Google data, which was used to adjust the model to social networks. Researchers plugged Facebook's data into the models to make the published predictions.

The study resulted in a publication which culminated from talks emerging from the Princeton Research Symposium. The title of the study is called "The social network disease: Epidemiology and the demise of Facebook."

Perhaps someone will be able to refute the study's findings, or argue why the models don't explain social networks or why Facebook should be different from Myspace. But for now, others have made the same argument in different ways.

From an economic perspective, Facebook has nearly maximized its users, which are limited to the number of real people in the world who can connect to Facebook. The company does not have a surefire way to monetize its user base and is still thinking of a creative answer. So far they are imposing more advertisements which alienates the majority of its users.