In the 1980s, when I first started studying popular culture, the introductory course (POPC 160) focused on “the most common part of our cultural heritage and our present living environment.” This environment was seen as consisting of popular beliefs and values, popular images of objects and people (icons, stereotypes, heroes), popular art forms (movies, books, music), popular events and rituals (Halloween, Christmas, family reunions), and all the normal activities of our daily lives. It was the “mainstream culture shared by large segments of the society,” that affects “the values we construct for ourselves” and reflects “ the values we have already constructed.” (All quotes are from the Popular Culture Reader, Third Edition, Bowling Green University popular Press, 1983.)
Since then, this definition has been broadened and amended to include most of our cultural environment.
The PCA website, for example, suggests that a perusal of the conference subject areas might provide a reader with an idea of the variety of topics that fall under the umbrella of popular culture. There are more than 120 subject areas. The subjects include folklore and education (which, formerly, would have been excluded) and they range from very specific (i.e., Jack London Life and Works) to more general (i.e., Music). Thus, the field of popular culture is very rich and diverse: popular phenomena are studied by many disciplines, from many points of view, using a variety of different methodologies.
In spite of its imperfections, the article “Popular Culture Studies”, published on Wikipedia (https://en.wikipedia.org/wiki/Popular_culture_studies#Bibliography), provides an informative overview of the history of popular culture studies at Bowling Green State University in Bowling Green, Ohio. It also offers many links to other relevant sites as well as a bibliography.