I think the technology to read the emotional expressions of students in a classroom is valuble because in paragraph 6 it talks about if you smile when a Web ad appears on the screen, a similar ad might follow . But if you frown the next ad will be differnt. The story talks about how your face expressions can say what emotion your feeling. For example if you raise your lips at the corners of your mouth , then squint your eyes slightly to produce wrinkling at the corners of your eyes , holding that raise the outer parts of your cheeks up, toward your eyes , it gives the looks that your happy because it all depends in your musccular actions . The computer can also tell when your faking a smile and when its real . Also in paragragh 8 its says that to an expert, faces dont lie, because the muscle clues are sometimes used to spot when a smile is not true. I think the technology to read minds is valuable because they tested it and they aprove that it is true that your face expresions show your emotions.