Abstract
How large and lasting are the effects of word-of-mouth (WOM) referrals versus paid marketing? What is the $ / € worth of a WOM-referral to an Internet social networking site? This study finds that word-of-mouth referrals have substantially longer carryover effects than traditional marketing actions. The long-run elasticity of WOM on site signups is 0.53; about 20 times higher than that of marketing events, and 30 times that of media appearances. Based on revenue from advertising impressions served to a new member of the site, the monetary value of a WOM referral is about $0.75 per year. By sending out 10 referrals, each network member thus brings in $7.50 to the firm; which represents the maximum reward the firm could consider to incentivize word-of-mouth referrals. Managers can use this approach and findings to benchmark metrics for both WOM and traditional marketing, to test changes in online WOM referral content, and to decide on the appropriate size of financial incentives to stimulate WOM.