I remember going to Summer Jam once, my freshman year of high school, because it was "cool" and a lot of my friends were going. I didn't really like most of the performances. That same year I went to Beatstock by myself because I couldn't find anyone else to go with since no one I knew liked dance music and of course I enjoyed it much more than Summer Jam. Hip hop was (and still is) considered "cool".
I also remember (and have an aircheck of) Q102 in Philly, a Clear Channel station, giving away tickets to Summer Jam 2003.