Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
We test empirically for network effects and preannouncement effects in the DVD market. We do this by measuring the effect of potential (incompatible) competition on a network undergoing growth. We find that there are network effects. The data are generally consistent with the hypothesis that the preannouncement of DIVX temporarily slowed down the adoption of DVD technology.