I guess the best way to describe cliodynamics is to say that it applies statistical methods to human society and history, in an effort to find patterns that can be generalized to predict future trends and events. The difficult part is determining which factors should be considered, as human societal behavior doesn’t lend itself to straightforward analysis.
One very interesting result is two cycles of political unrest that have occurred throughout human history and can even explain the timing of the recent Egyptian uprising. The first cycle repeats about every 200-300 years and is the result of labor supply outstripping demand due to population growth. This forms a class of elites who end up fighting for power. The second cycle occurs about every 50 years, or approximately two generations. Here in the United States, we’re due for the next one sometime around 2020.
In his Foundation series, Isaac Asimov wrote about psychohistory, the science of predicting the behavior of human societies. Cliodynamics is a step in that direction.