The beauty of On Demand Services is that, you can access and avail service any time you need, but for premium ones you need to pay for it. There are also challenges in maintaining these kind of services, as a corporate if you have On Demand Services these should be accessible by your customers at any time through internet and these customer can be from various region and from a region there might be different types of customers (Sex, Age, etc) accessing the service and so you need deliver the appropriate content based on parameters such as region, customer profile, etc. There are content Management systems (CMS) available which can index the content based on parameters and store it, qualify the request for content based on parameters such as region, customer profile, etc and provision the appropriate content. So, Content Delivery is managed through these systems but on pricing part, On Demand Service Provider might come up with different prices for the same content in different region and also packaging of services using various combinations of services as promotional activity and further more invoicing and collecting the payments, before provisioning of the content. CMS are not capable of packaging & pricing of the services, invoicing & payments collection, this part can be handled by Billing Systems.
So, On Demand Service Providers can have good turn over in this model by having an efficient CMS and Billing Systems in place.