1. A system for matching a venue with one or more performers, the system comprising: a database that stores information about venues for holding performances, performers that perform acts of entertainment, and fans of the performers; a computer that has access to the database and that is configured to: receive indications of interest from fans, wherein each indication of interest is an action taken by a fan that shows that the fan has interest in a specific performer; determine, based upon the indications of interest, interest metrics representing individual fans' degree of interest in specific performers; determine distances between geographic locations of fans and venues; determine participation metrics representing each fan's rate of participation in past performances; determine social influence metrics representing likelihoods that fans will be influenced by actions of others; weight the interest metrics, distances, participation metrics, and social influence metrics according to their relative importance in calculating the likelihoods of attendance; calculate likelihoods that specific fans would attend a performance by a specific performer at a specific venue, wherein the calculation takes into account the interest metrics, distances, participation metrics, and social influence metrics; calculate an estimate of attendance at a performance by a specific performer at a specific venue by summing the likelihoods that specific fans would attend the performance; and use the calculated estimate of attendance to match a venue with a performer.