Cost of servers & bandwidth 
staunch: If you mean serving audio files 100k times (once per "user") then it's not expensive unless the files are especially large. If you're serving over HTTP then use high performance web server (like nginx or lighttpd) and a dedicated server.I highly recommend ServerBeach myself -- especially if you're going to use any significant amount of bandwidth. For $75/mo you can have a dedicated server and 1200 GB/mo transfer.http://www.serverbeach.com/catalog/cust_ref_landing_new.php?... ($100 off w/my referral code ($250 for me))http://www.serverbeach.com (no referral code :D)