Apparently, Road Runner has begun to put a 15 GB/ month cap on downloads in some of their markets (e.g. Western Ohio:
http://www.roadrunnerohio.com/tiered_services.htm).
I assume that they are doing this in some test markets. If you download more than 15GB, you have to pay more. This is probably their way of combating file sharing as they are both a content providern (AOL TW) and internet provider (RR).
If they decide to implement this cap in all of their markets, then it's time to move to DSL or some other alternative. I thought broadband meant unlimited fast downloads....
Get 'em while you can!