Cost of servers & bandwidth 
brk: Committed bandwidth can be had in many datacenters these days for around $50/Mbs  ($50 for every 1Mbps of committed bandwidth).  Or you can do 95th percentile burstable bandwidth as well (or combine the two ($100/mo for 2Mbs plus ~$100 for every 1Mbs over 2Mbps, billed 95th percentile)).About $400/mo for a half cabinet and some power.  You're in the neighborhood of probably $500-$900/mo.Why colocation instead of some shared or pseudo-dedicated server some place?  Because (IMO and IME) you're better off with any site that is going to do streaming and potential sustained throughput in colo facility with fixed costs.  Places like Rackspace just love when you go 10x over their pitiful limits and your $200 monthly plan is suddenly $4000.  Kind of hard to budget for.Of course, I'm also biased, having an interest in a colo facility :)