I posted about this earlier http://deancollinsblog.blogspot.com/2007/03/note-to-riaayou-dont-run-whole-world.html but wanted to flag again that this decision to charge per listener is just insane and is going to drive out some of the most innovative providers in the music industry (eg. pandora etc).
I just came across this great article which pretty much covers all the key points so check it out (gets better from page 2 on) http://www.salon.com/news/feature/2007/03/20/copyright_royalty_board/?source=whitelist
Pretty much anyone who is streaming audio content is just going to relocate their servers internationally (Panama anyone?) and continue on as normal. It's just a farce only the RIAA/SoundExchange clients (the record labels) just haven't noticed and haven't realised how the end game is going to resolve.