I gave some serious thought to using Amazon EC2 as a server platform. Unfortunately the $0.10 per hour works out to about $72 per month, which exceeds the $50 per month I'm paying for my DSL with static IPs. It's still something I would consider for a commercial application. It's a virtual machine in the cloud. How cool is that?

This also drew my attention to Amazon S3, which is a way of storing data very similar to the way I store it in AMI. The advantage, presumably, is higher reliability. Unfortunately I don't know exactly how reliable S3 is. And calling it "cloud" data storage may be somewhat misleading. I suspect it's still hosted on one or more servers which, if they go down, leaves you SOL. True cloud storage would be distributed. I did find such a service: OpenDHT, where you can donate a portion of your local storage to the cloud and in return be able to store data of your own in the cloud. The disadvantage of this service is that the data has a limited lifetime. That kinda kills it for me.

But the actual technique of storing data in a flat space of records (aka nodes or documents) each of which can have any number of arbitrary attributes (aka fields or columns) holds much interest for me. Such a technique is much more flexible than the traditional relational techniques that require pre-defining tables. Combine that with OSGI and you have a truly dynamic system.