Its not a downside as much as just something to think about, but: In a double sided referral (especially when giving money) you are splitting the discount betw

Its not a downside as much as just something to think about, but: In a double sided referral (especially when giving money) you are splitting the discount between two people. This can mean that the new customer gets less of a discount. If you have $10 to acquire each new customer, you have one option where you say "$10 off for new customers!" and hope people see it, or you split that amount "$5 off for both of you if your friends sign up". The benefit of the latter is that you are essentially offering a deal to get high quality referalls. However, you might be offering less to the end customer. The genius of giving away product like dropbox has (or giving store credit) is that the cost to you is alot lower so you can give away more for double ended referrals. Then, everyone wins. The deal is better, both parties get the deal, and the company is happy. We think its a really interesting problem area that we're trying to solve.