The motivations behind why popular culture embraces the icons is does or why it believes certain truths as well as how individuals gain power in that particular culture can have a great deal of relevancy to historians who seek to understand a better idea of the past. Popular culture is driven by individuals' perceptions and understanding, and this can be studied in order to gain a wider view and conception of social orders. For example, popular music and popular art forms can reveal much about the preferences and appreciation of a culture. Fashion can help to illuminate much of cultural perceptions and subtleties reflected in dresses. As culture itself has undergone a massive transformation in the 20th Century, analyzing each decade's culture helps to provide a framework and paradigm in order to better understand it.
I am always torn about how much I should use popular culture when I teach history classes. On the one hand, popular culture surely must say something about what life was like at any given time. However, I think we too easily slip into the trap of assuming that certain elements of popular culture reflect the lives of everyone living at the time. We end up stereotyping a time and place.
I do like to teach about popular culture. Since my students are so immersed in popular culture, they tend to be interested in looking at what their counterparts in past ages would have experienced. So, in that way, popular culture is quite helpful.
However, one must be careful in looking at popular culture. A prime example of this is the counterculture of the 1960s. We tend to look at them as being representative of all American youth at the time when they clearly were not.
In this age of increased interest in interdisciplinary studies and in popular culture, it's not surprising to see many cultural historians assigning popular novels from the past in their history courses (or, for that matter, to see scholars in literary studies applying New Historicist approaches to the texts that they study and teach). Popular novels, such historians probably reason, did not become not popular by accident; they must have spoken to a wide range of readers for some particular reason at that particular moment in time. Thus, it may be possible, though a study of both the novel and the external history, to understand how the two relate to one another. The novel (or other some other manifestion of popular culture) may thus breathe a little life into the otherwise often statistics-based history of census data and other "dry" historical documents.
I would expect people to most like things that reinforce their views or that enable them to adapt to painful social changes in a palatable way. So, for example, the historian of the Civil Rights Movement might be interested in reading and teaching Harper Lee's novel To Kill a Mockingbird, which was published in 1960 and which enjoys immense popularity among white readers today, as a palatable and fictional treatment of the radical transformations of American culture, particular in the South, brought about by African American agitation for equality. The novel is set in the Depression era, but many of the issues that it addresses -- including segregation and lynching, among others -- were very much alive in the South in the mid- to late-1950s.
The three links given below address the use of fiction and other forms of popular in the history classroom. You are likely to find other useful discussions at the World History Connected website.