Those not initiated in the mysteries of databases, i.e. most of us, may think that Amazon.com's new SimpleDB service is competition for established databases from Microsoft, Oracle, and IBM. It's not. Nor is it, in the lofty language of Web-computing evangelists, a "cloud-based" alternative to large Web databases. But it's probably a perfect match for your stupid Web 2.0 startup, which makes it a genius move by Amazon.