Answer:
At the beginning of 1960, there were 5,843 national interest groups in America, and there number increased to 10,308 in 1970, and to 14,726 by 1980. The media played a huge role in the expansion of interest groups since one of the major roles of interest groups is to build an agenda, i.e. to create an awareness of their issues and try to influence politics.
You might like or not President Trump, but the media played a huge role in getting him elected. The same happened during the 1960s and 1970s, except that instead of the internet, interest groups used TV, radio and printed media. Mass media outlets helped interest groups create their agenda.