ple and plants. A request for viewers to send in their gardening photos generates several hundred e mails with attachments, a significant percentage of which contain uncompressed files. Someone has the Herculean task of sorting through these pictures, deciding which ones to keep, which ones to use and how to describe them in the data base. User-generated content is therefore not free and indeed has a significant cost that is increasing over time. 21.24 The Hidden Cost of Content - Trigger Moments Broadcast content may also have trigger moments, voting for example in a talent show. Instead of an avalanche of photos the problem is now an avalanche of SMS messages or phone calls that have to arrive and be dealt with by a specified time in a specified way. An organisation now exists to monitor and manage and regulate the operation of phone-in promotions. Several producers lost their jobs for failing to manage this process and participa- tion revenues in the UK reduced significantly as a result. Making Telecoms Work 21.25 The Hidden Cost of Content - Delivery Cost Trigger moments can create loading issues that can only be fully addressed by over provision- ing store and forward and onward delivery bandwidth. Overprovisioning store and forward and delivery bandwidth both over the air and through the network implies substantial un- derutilisation for most of the time. Additionally, content has different delivery requirements ranging from best effort (lowest delivery cost, highest buffer cost), streaming (audio and video downloading), interactive (gaming) and conversational (highest delivery cost, no buffer cost). Supporting all four types of content simultaneously adds substantial load to the network. The administrative effort counted in software clock cycles is significant and outweighs any benefits theoretically available from multiplexing best-effort data into the mix. 21.26 The Particular Costs of Delivering Broadcast Content Over Cellular Networks The DTV alliance analysed delivery costs and delivery revenues in a 