Yeah, a random feature would be nice to provide some variety. And maybe a "trending" or "movers and shakers" list for songs that aren't necessarily in the top 40 but are still getting buzz on Twitter.
I second this. The only downside to this that I see is that it would be less mainstream music. Why this is bad is mainstream music (although not always that great) targets what most people would like. This would mean that it is unlikely that there would be the odd song that would be really jarring to someone. I figure this is a bad thing as you want something for people to listen to in the background.
I cannot imagine that this is really meant as a music discovery tool as it is meant to be the top 40 most mentioned things.