As E-Commerce executives consider the meteoric rise of consumer companies such as Airbnb, Dropbox and Uber, it can be easy to overlook two important facts:These companies felt the same user acquisition challenges as you do today. These challenges pushed them to innovate new social sharing mechanisms using technology; andThe strategies these companies used are not exclusive to their business model. In fact, they would work just as well for online retailers.E-Commerce brands have the same opportunity to take advantage of referral marketing. Marketing executives are aware that Refer a Friend can be profitable.