Commercial tools
There are many commercially available tools on the market that do the hard job of maintaining and tuning data for you. To use most of these tools, you will have to request demos and get a pricing quote.
Barilliance
Barilliance provides many different types of recommendation services, along with a website recommendation system, personalized emails, and much more. They also offer custom widgets that you can directly apply to your online store. For more information, visit Barilliance's official website at: http://www.barilliance.com/.
Softcube
Softcube provides services for user recommendations on websites, along with personalized emails and push notifications. You can opt-in for a 30-day free trial of their service. For more information, visit Softcube's official website at: http://www.softcube.com/.
Strands
Strands also provides different algorithms, including collaborative recommendation and content recommendation, along with many different business logic examples and models that...