It's all about Optimizing Rich Media Content

YouTube now accounts for 13% of total global mobile data bandwidth, and the site represents 40% of all video streamed globally over mobile devices according to data collected in Allot's MobileTrends Report. They go on to observe that 35% of all mobile data bandwidth is now taken up by video, with web browsing consuming 29%, HTTP downloads accounting for 16%, and P2P taking 15%. VoIP and IM account for 3% while all other apps only represent 2%.

This is further evidence that it's all about optimizing rich media content - and especially in the RAN - given rich media's disproportionate impact on mobile broadband service delivery costs (backhaul bandwidth) and user experience (localized busy hour congestion). The rest of the data traffic is essentially noise on the link.