This is a question that could be answered in a number of different ways, depending on how one defines “mass communication” and what technologies one considers to be part of such communication.  One definition of mass communication is that it is communications that are sent by one party and aimed at a large and largely anonymous audience.  If we use this definition, we could say that mass communications have been around a very long time.

Thousands of years ago, governments were already engaging in mass communications.  They would erect statues, some of which had messages carved on their bases.  These were early attempts at mass communication.  Mass communications really took off when the printing press was invented and paper came to be widely used.  This allowed more people to craft messages that could be printed and then disseminated to essentially anyone who could read.    

After that, mass communications did not change much until the advent of electrical communications.  The invention of the telegraph allowed people like politicians to transmit their speeches to faraway places essentially instantaneously.  This process was accelerated by the invention of the radio.  Radio allowed those speeches to be broadcast to huge audiences on a live basis.  Since then, technologies such as television and streaming audio and video on the Internet have added visual images to this process and have allowed people to receive broadcasts on their computer or their cell phone or other device.  This means that mass communication can be directed at almost anyone, anywhere, at any time.

Thus, mass communications have undergone major changes in their history.