It’s the first instance of which I’m aware of someone offering DBMS-level services in the cloud. Arguably, GoogleBase is a competitor, but I’ve always viewed that as more aimed at eBay and Craigslist and less about cloud computing.
While most SaaS-type applications are indeed applications (e.g., NetSuite, Salesforce), Amazon has been coming at cloud computing from an infrastructure-up, rather than an application-down, perspective. Previously Amazon launched lower-level services including EC2 (elastic compute cloud) and S3 (simple storage service) in the same “pay as you go to use our infrastructure” manner.
I’m told Amazon got into cloud computing because, due to the spikey nature of retail, they have built a massive infrastructure to handle demand peaks (e.g., Christmas) that goes largely unused most of the time. AWS is their attempt to monetize it.
Finally, here’s the pricing for SimpleDB: Machine Utilization – $0.14 per Amazon SimpleDB Machine Hour consumed (normalized to the hourly capacity of a circa 2007 1.7 GHz Xeon processor). Data Transfer Structured Data Storage – $1.50 per GB-month
$0.10 per GB – all data transfer in
$0.18 per GB – first 10 TB / month data transfer out
$0.16 per GB – next 40 TB / month data transfer out
$0.13 per GB – data transfer out / month over 50 TB
Machine Utilization – $0.14 per Amazon SimpleDB Machine Hour consumed (normalized to the hourly capacity of a circa 2007 1.7 GHz Xeon processor).
Structured Data Storage – $1.50 per GB-month