The tech behind Amazon's recommendation features -- the product lists with the "Customers who bought this item also bought," label -- were key to the company's early growth and a delight even for its founder. The tech behind it is now for sale.

Bundled with other Amazon cloud services, personalized recommendation features are a sign of how much the cloud computing market is expanding. Today, providers don't just sell data storage. They increasingly sell technology that would normally give them a market advantage.

Last year, the New York Times interviewed a researcher who predicted that large corporations will increasingly outsource their technologies to the cloud service providers:

John Dinsdale, chief analyst at Synergy Research, predicted that the cloud giants will get bigger and capture a steadily rising share of corporate technology spending — especially as they add new capabilities, like machine learning and artificial intelligence, to their services.

These technologies all share a base in AI and machine learning, and are too expensive for most companies to develop. Cloud providers like Amazon, Microsoft and Google are betting they'll will make ideal business products.

In some cases, cloud providers promise to replicate the features that made their own companies so successful:

• Amazon, Microsoft and Google offer machine learning services that comb through data (like sales histories) to produce forecasts.
• AWS customers, as mentioned above, can enable personalized recommendations similar to those found on Amazon.com.

Other services are aimed at making inventory management and data recognition more efficient:

• Amazon, Microsoft and Google sell services for facial and pattern recognition in images, video, audio and text.
• Microsoft's own Azure Kinect camera, a rebuilt version of their discontinued Xbox gaming camera, was recently released for enterprise use. Its depth camera can be taught to recognize inventory items, aid in surgery, or recognize faces.

Other features are more abstract.

• All three also offer Internet of Things services to connect physical sensors-- like temperature gauges, smart locks, home appliances, machine parts, inventory tags, etc.-- to applications and dashboards for tracking and remote control.