[secret]

That's a good point on #3. Just to toss out an idea- what if the service offered tracking of the referral and could provide some sort of analytics to help retailers optimize their social campaigns.

For example- I complete a purchase on Retailer A and I am presented with your widget and: maybe I get a rebate on my purchase, or a coupon for next time if I share on Facebook, or maybe the rebate goes into effect if a referral completes a transaction. You could use something like bit.ly to track the links. Ultimately, one of my friends sees this on his feed and goes to Retailer A and makes a purchase.

The retailer would be: 1. incentivizing the user to share and 2. be able to see some sort of stats analyzing which campaign is preforming better.

I think I would definitely be tempted to pay for something like that.