Mathematical modelling of editorial decisions: Should novelty or popularity be the primary criterion? Using a simulated version of Digg.com, they found the interesting result:

The simulator—a virtual world that reproduces the way people digg stories—was allowed to run with each strategy for the equivalent of a year. Measured by the total number of diggs in this period, the novelty-based strategy for ordering stories on the home-page proved far superior to the popularity-based one. In other words, digg.com is doing the right thing. However, if the half-life is increased, the situation changes. When it rises above 350 minutes, sorting stories according to their popularity rather than their novelty generates more diggs. This switchover is mathematically analogous to phase transitions in nature, such as the way water freezes as soon as the temperature drops below 0°C.