I find these sort of things more useful in theory than in practice. I used to think that the architecture described in this article was a good goal. I have sin

I find these sort of things more useful in theory than in practice. I used to think that the architecture described in this article was a good goal. I have since seen systems built with the many layers of indirection (and pass through service layers) and they are very difficult to maintain. Simple interation bugs become hard to discover because the leaky abstractions built on top of one another interact in complex ways. They are also very difficult to optimize for scale- if you don't own your data, it's hard to invalidate your cache, as just one example. This onion stinks. If you are obsessed with creating a service layer, stick with Fowler: http://martinfowler.com/eaaCatalog/serviceLayer.html http://martinfowler.com/eaaCatalog/serviceLayer.html