Clear Chanel has shifted their Active Rock in Birmingham to Mainstream Rock. This comes shortly after Atlanta saw the "merging" of a Classic Rock (Rock 100.5) and Active Rock (The Bone) into the new Mainstream Rock 100.5. I believe this is the future of Rock radio as classic gets too old and Active fails to deliver a strong enough product. We'll see more and more markets doing Mainstream and those that put it on a strong enough signal with quality personalities will see some great results.