Is the "medium is the message" ?

Marshll Mcluhan coined the phrase "the medium is the message". This means that the medium influences how the message is perceived. In his book - 'Understanding Media', McLuhan describes the "content" of a medium as a juicy piece of meat carried by the burglar to distract the watchdog of the mind. He believed that the content might have little effect on the society. For example, if a television broadcasts children shows or violent shows, the effect of television (and not the shows) on society would be identical and profound. He pointed to the light bulb as a clear demonstration of the concept of “the medium is the message”. A light bulb does not have content in the way that a newspaper has articles or a television has programs, yet it is a medium that has a social effect; that is, a light bulb enables people to see during nighttime that would otherwise be enveloped by darkness. He describes the light bulb as a medium without any content. McLuhan states that "a light bulb creates an environment by its mere presence."Likewise, the message of a newscast about a heinous crime may be less about the individual news story itself — the content.

Marshall Mcluhan's theories are not universally accepted. There are some theories that go against his way of thinking.
For instance, Consider a physical recording medium like a CD or DVD. By itself it's an empty vessel. The "message" is the information contained within that medium, whether it be music, a film, software, or some other information. The message is what provides the value -- the actual recording medium is often not very important. You may pay $20 for a CD that contains music, or you may pay $300 for a CD that contains certain software. But the physical CD's are essentially identical except for the information they contain. This price difference isn't due to a difference in the medium but rather due to a difference in the message.
For example, in most cases your job title represents the medium of your career. Career media include being an attorney, a salesperson, or a computer programmer. Think of your career medium as the vessel through which you work. Much like a recordable CD, your career medium is an empty container waiting to be filled. If you identify yourself as an attorney or a salesperson or a computer programmer, that doesn't give you any sense of the value your work provides. Those professions are conduits for providing value, but they contain very little value in and of themselves.It isn't hard to recognize that the primary value comes not from the medium of your career (i.e. your particular job) but rather from the message of your career. The message is what you bring to your career. It's what fills the otherwise empty container.