Have seen a lot of these services, but this is definitely worth checking out. I think Multi-armed bandits are the way to go with optimisation, and just won Startup Asia's hackathon using this technique for a tinder-style app. A lot of people talk about learning from their customers, but few know how to really do it - understanding the math behind what's going on gives me much better confidence when deploying this type of service... Great work sharing it in this way.