Facebook filed for a patent for a program that will spy on Facebook users through their webcams. This would allow Facebook to determine in content made you happy or sad. Facebook will try to give you more content what makes you happy.
Facebook plans to secretly watch users through webcams, patent reveals
Facebook is planning to secretly watch and record users through their webcams and smartphone cameras, a newly discovered patent suggests. The document explains how the company could use technology to see how your facial expressions change when you come across different types of content on the site.