The medium is the message

This article was hard for me to understand I googled the phase and it said that "The medium is the message" has to do with the way that people perceive a message. In the article it talked about how IBM makes computer equipment its what people think when they here IBM, but what IBM really does is process information.  Marshall McLuhan states in the begging of this article that technology has destroyed depth of involvement in work. I think he means that we depend to much on technology. An example might be how the self checkout lines at stores eliminate jobs for people we might have needed a job. He also states that I.Q test are bias and is based on continuous habits because that is what is considered intelligent and it eliminates the "ear man" and the tactile man. I wonder if this means that in order to be intellectually successful on I.Q. test you have to be a basic person with one specific way of understanding things.