the beanstalk programming model: http://aws.typepad.com/aws/2011/01/aws-beanstalk-programming... This is pretty cool, but for people targeting it because of no-hassle infiniscale, it must be noted that you either use SimpleDB or good old MySQL for storage. So AppEngine is still winner in that area, imvho, but it's great to see competition.
You can specify any JDBC connection string. Thus, you can point to any type of DB storage technology you want. The article is just highlighting the AWS DB offerings.