DeepEyes produces video-based A.I. systems for a variety of people detection, tracking and counting applications.  DeepEyes’ systems can detect general emotions, gestures, identify specific people, etc.

An couple examples:

According to one section of their site:

In surveillance settings with several persons the DeepEyes emotion recognition can identify with high accuracy general emotions like attention, surprise, disgust or indifference on human faces. Also,the technology can tell the duration of attention or the line of sight in an extremely accurate way. Additionally, persons can be categorized in terms of approximate age, gender etc. This enables to effectively analyze customer behavior and adapt to changing demands and expectations. The technology works with data from normal cameras. DeepFace can classify customers in terms of age, gender and optional categories of clothing size. It can be used to analyze customer-facing marketing and sales activities.

Remarkable how much analytical power can now be achieved through quite inexpensive, standard camera tech.  Amazing stuff.