Hits and misses: Herd behavior and online product popularity

This article presents the results of a market experiment in which the perceived popularity of programs on a large commercial online system were manipulated. The download counts of software, which indicate how many previous users had obtained a software program, were artificially increased by repeated downloading. This manipulation was done to one member of a matched program pair, with the manipulation levels set randomly to achieve a balanced experimental design over a set of matched pairs. Subsequent downloads of the programs made by the service's subscribers were then recorded. Substantial additional downloads were induced by the manipulation. Some consumers apparently are drawn to market leaders, further increasing their lead. This raises an important issue regarding the need for verifiability of online popularity measures.