Thought of a useful service for cloud computing

Previously I mentioned that I find it a little difficult to think of a useful service that could be put in the cloud, enjoy the full capabilities of cloud computing and yet can be justified from the business perspective. Just recently read an article about travel websites and it hit me that a ticketing system would be a very useful cloud computing service because:

1. Demand can scale up easily during peak seasons (e.g. F1)
2. With a hybrid cloud model, it will not be difficult to remotely provide data to the "ticketing cloud" on the newest information
3. Service providers can concentrate on what they are selling and let the cloud computing providers worry about the ticketing infrastructure and application

If you look at the process for buying tickets in Sistic or cinemas, there is fundamentally no difference in functionality between these providers. I wonder if any cloud computing vendor is providing such a service. It does require some tie ups with the merchant banks to handle all the transactions though. Hmm...