Game popularity follows a power-law

To determine the distribution of on-line game popularity, we analyzed a nine-month subset of the GameSpy data set described in Section 2, starting March 1st 2003. Of the games, we consider only the top 50 games, as the remaining games averaged a minimal number of players throughout the trace. To average popularity rankings we first calculated the rank ordering of the games and the number of players at a given rank for each day. Then we averaged these daily rankings over the nine-month period to show the distribution of players across the games regardless of fluctuations in individual game popularity. Figure 6 shows the popularity data on a log-log scale. As the figure shows, this distribution is heavily skewed in favor of the most popular games, with the first ranked game having over ten times the number of players of the next most popular. This distribution of popularity is most similar to a power-law distribution. Power-law distributions are of the form $y = ax^\lambda$ and occur in a number of places including the frequency of words in the English language, the popularity of web pages, and the population of cities. An intuition for these distributions is that whenever choices are made between many options, and each choice affects other choices, the choices tend to pile up on a few popular selections. Games and servers create communities: in selecting one, each player's choice affects and is affected by the popularity and reputation of that game or server. A perfect power-law distribution would graph as a straight line on a logarithmic scale in both the $x$ and $y$ axis. The relatively straight line (correlation coefficient -0.98 for a simple linear regression) demonstrates that the GameSpy data does follow a power law distribution. This distribution has an interesting, albeit unfortunate, implication for provisioning server resources for on-line games: the host must plan for several orders of magnitude of change in popularity (and therefore resources) in either direction. As a result, this indicates that on-demand infrastructure can significantly reduce the costs and risks of launching and hosting on-line games.