Popular culture has recently gained more attention in academics for many reasons. Previously, it was put down as less intellectual and more basic than the "high" art - which in past centuries tended to be produced by members of the upper class.
"Culture" used to be known as the intellectual elite in the arts, science, and society. It wasn't until mid 19th century that culture or "cultures" started to mean different societies, ethnic groups and classes of people. And it wasn't until recently (20th century, especially the postmodern era - after WWII) that these cultures (popular culture as in folk and mass culture) became viewed as objects of legitimate academic study. Eventually, even the so-called "primitive" societies were viewed with the kind of complexity that the so-called "civilized" societies - i.e. the Western World - were (example, Claude Levi-Strauss' work).
The division between high and popular culture used to be based on what was thought to be intellectual. Nowadays, most scholars see that this was a political division - one which gave upper classes more opportunity for education - but also a fundamental class-centered and often eurocentric way of thinking. Certainly from the most recent cultural revolution, the 1960s on, cultures or popular culture have received more attention - not just from an anthropological perspective, but also sociological: receiving interest as an intellectual study as legitimate as high culture. In other words, the division between high and popular had changed: Now, pop culture receives more attention as an academic subject because it is interwoven with "high" culture; and because the line between civilized/primitive has also been questioned. Just going back to Strauss, social (literary, and others) critics began to see that the view of primitive societies was eurocentric and sometimes downright racist. Some of these critics came to see primitive societies as less industrialized, but not necessarily less civilized.
One more thing: the "public sphere" - public spaces where pop culture, news, politics are discussed has increased over the years - growing cities, newspapers, television, internet, blogging. The public has had more access to information and communication, so studying the pop culture of the public is not just to record what's popular, but to show how it contributes to the world. Critics like Walter Benjamin and certainly Marxist critics didn't like the mass produced standardization of art, but they did see the immense possibility for revolution via popular art for the main reason that it could reach a lot of people. So, another important reason pop culture is becoming as worthwhile a study as "high" art is that pop culture is seen as either a potential social pacifier or a social/individual liberator.