Word of mouth (WOM) is becoming increasingly recognized as an important form of promotion, particularly within professional services environments, where credence qualities play a critical role in consumers' choices. The present paper seeks to explore the factors that are likely to enhance the chances that receivers of positive word of mouth might be influenced by such information. The study examines findings from six focus group discussions and 103 critical incident forms. The findings suggest that the potential for WOM to impact on perceptions or on actions depends on the nature of the sender-receiver relationship, the richness and strength of the message and its delivery, and various personal and situational factors. The findings are tentative and based on a relatively small sample; however, they provide a useful framework for future research into the process of WOM. The importance of WOM in marketing, particularly professional services marketing, is widely accepted; however, little is known about how to enhance its occurrence. The paper provides marketing managers with a better understanding of the factors likely to influence receivers of WOM. Most WOM research focuses on the sender of WOM. In contrast this paper provides insights on the impact of WOM on the receiver, something that is currently a "black box" in the marketing literature.