As a part of the testing, the machine bounced radio waves off actors who recreated a range of emotions. The breakthrough makes it easier to accomplish what scientists have tried to do for years with machines: sense human emotions.
Though the article sounds a little click-baity, the research was led by Dina Katabi who directs MIT's Wireless Center and was awarded the MacArthur Fellowship, so I'd tend to believe the claims a lot more.
This sort of technology is also less invasive than trying to detect emotion through video recordings - although the privacy issue of this being deployed at scale without user knowledge definitely needs to be addressed.