First, we should note here the difference between mass and personal communication. An email, a letter, a business memorandum, an instant message, or any document intended for a limited readership is not an example of mass communication. The definition of "mass communication" refers to some form of communication that reaches a significant proportion of a population. The enabling technology of mass communication was print, and especially newspapers, which could reach a large portion of the literate people of a nation. Subsequently, radio and television created a genuine mass audience. In the United States, certain television programs claimed over half the potential audience at a given time slot.
The internet has contributed to fragmentation of mass media. In the past, one could argue that mass media built a sense of community as millions of people simultaneously sat down to watch the evening news, sporting events, or other popular television shows. This mass audience first began to fragment with video recording technology which allowed two major changes to viewing habits, the possibility of time shifting and the ability to skip over advertising.
The internet intensified this trend of fragmentation, with many people watching video context over streaming services at their own convenience. It has also allowed the proliferation of a far greater number of channels and of people to search independently for individual pieces of content rather than packages of paid channels, a phenomenon described as "cord cutting" which has led to rapid decline in cable television subscriptions.
The fragmentation of mass media in one sense creates a new degree of flexibility in that people have infinitely more choices of what to watch or read. Unfortunately, it also has the negative effect of encouraging tribalism, in which people live in media bubbles that echo their own preconceptions, with, for example, people of a give political disposition only viewing "news" shows slanted towards reinforcing their own current biases.