Vote brigading
Vote brigading is massively coordinated online voting. It refers to the practice of affecting reviews or scores on websites that feature crowdvoting, such as online stores or review websites, by calling on large numbers of people to submit reviews, thus boosting or decreasing ratings artificially. This may be done for political reasons, for example, to harm the commercial prospects and credibility of films dealing with controversial or sensitive subjects. Vote brigading is a form of participation bias, which can decrease the reliability of the aggregated score.