Scaling Bumper Sticker: A 1 Billion Page Per Month Facebook RoR App
highscalability.com
highscalability.com
However, in my experience, the Bumper Sticker app is often very slow and clumsy to use. Ironically, I often use it as an example when speaking of Facebook apps that don't do a particularly good job of scaling.
Bumper Sticker was an experiment to see how fast the Light Engineering Development (LED) team at LinkedIn could build a Ruby on Rails Facebook application.
Based on that quote, I don't think they had a financial goal with it... although now might be a good time to think of one.