Smile: Loyalty Program Rewards

Excellent, excellent app. I've tried all of the customer relationship apps available for Shopify, and nothing comes close to being as thorough and well implemented as Sweet Tooth. It's been on my shop dappernotes.com for a bit now, and the response is already great.
Plus: you can't beat a thoughtful pricing model like this one: if you have enough active customers, then the monthly fee is a drop in the bucket to keep them coming back.
Finally: the customer service response is AMAZING. And when it comes to putting anything on my website, having a product with a real dedicated team makes all the difference in the world.