We were looking at the engines plugin for a while and despite all the flame wars around it, Me and Raphael were somewhat convinced that it would be needed somehow in future. I kept trying installing it but failed. So a little context here, we ported our application from Rails 1.2 to Rails 2.02. And it was this version which we "freezed" under the vendor directory. And installing engines plugin on that version was failing. From my past development experiences, and from observing some colleagues for a while in my career, I've a nature of being very lean and mean about things.