A Revenue Model For A Web Service Economy

I prefer to consider history as a guide.
The best solution would be a layered model similar to the blender on my kitchen counter. You pay a one time fee for posession of a blender, but you must also pay a monthly service charge for the electricity it uses and any fees associated with the items being "blended".

Here is how I would break it down:
(Using the layer model from Phil Wainewright)

• APIs: A fee based on usage
• Aggregation services: A fee based on usage
• Application services: A one time ownership fee
• Serviced clients: A one time ownership fee unless included with the application service

Esentially this duplicates what we have now. The real problem is actually getting people to understand why they should pay.