There have been several studies that show statistical proof that consumer advocates work. A study from the Wharton School of Business, R&G Technologies, and McKinsey all revealed the benefits of consumer advocates:

Consumer advocacy reduces the cost for acquiring new customers.A referred customer has a 16% higher life-time value.Referral leads convert about 30% better than leads from other channels.Referral leads take less time to actually convert. (Less decision time on the part of the referred customers.)Word of mouth is behind 20% – 50% of all purchasing decisions....

Via Jeff Domansky, Os Ishmael