Definition of "popstream"

Just as the gang peace movement desired to mainstream hardcore bangers into civic society, The Chronic wanted to drive hardcore rap into the popstream.

2011, Jeff Change, Can't Stop Won't Stop: A History of the Hip-Hop Generation, page 420

Genuine remixers of sound and traditions, and typically estranged from the cultural popstream, each of these cultural brokers maintained vast collections of fresh material enabled by networks of exchange […]

2013, Simone Krüger, Ruxandra Trandafoiu, The Globalization of Musics in Transit