Nathan Torkington - A Week in the Valley: Ning:

"It's just like Rails in the sense that it makes it easy to build a web app. Rails puts "hello world" one commandline away. Ning puts a full real big app one click away. Rails is a framework built around conventions. Ning is a set of libraries, and Ning apps are built using those libraries. There's actually less of a learning curve for programmers in Ning than there is in Rails.

[...] Their storage engine is interesting. Every object has ID, app, user, tag, and type as metadata, and holds arbitrary key-value pairs. That's all the storage engine does, so it's very web loose-coupled. If your appointment data points to my address data, I can delete my address data and your appointment's left pointing to nothing."