How to help people get credit for recommendations?

• Incentivize the Recommender
• Incentivize the Recommendee
• Incentivize the Establishment who gets business

Are there already products or services that do this?

Products

• Groupon
• Living Social
• Amazon Affiliates
• LeafIt?
• Yelp?
• Foursquare?
• Others?

Services

• Companies often offer referral bonuses for Employee's who recommend other's to work there
• Business offer discounts through coupons and ask where business comes from - How'd you hear about us?
• Amazon Affiliate Program