Heartland rock is a genre of rock music that developed in the 1970s and reached its commercial peak in the 1980s, when it became one of the best-selling genres in the United States. It was characterized by a straightforward musical style, a concern with the average, blue collar American life, and a conviction that rock music has a social or communal purpose beyond just entertainment. The genre is exemplified by the commercial success of singer-songwriters Bruce Springsteen, Bob Seger, Tom Petty and John Mellencamp, along with less widely known acts such as Southside Johnny & the Asbury Jukes and the Iron City Houserockers. It was also associated with a number of country music artists including Steve Earle and Joe Ely. In the 1990s, many established acts faded and the genre began to fragment, but the major figures have continued to record with commercial success.