If a "BaaS" for a web app sounds appealing, try http://github.com/adelevie/parse_resource.

It lets you use Parse in a Ruby/Rails app with a very ActiveRecord-y API. By using it, your web app gets the following for free: documented REST API, documented iOS and Android SDKs, and the guy who helped scale Scribd is your DBA.

I've been using parse_resource to make some throwaway apps, and I'm currently "dog-fooding" it for a production app. I've found that the schema-lessness and zero-db-admin makes prototyping a snap.

I'm fairly active in developing it, and would really like some feedback, feature requests, and contributors.