once again i completely agree with steve.
i don't think you can truely know what a plateau is unless you are doing compound movements. and if you using them you won't know what a plateau is until you have exhausted every effort to progress without gaining a thing.
i think the beauty of it is that most of us will never fall into the advanced catagorie. it would take decades of training and dedication to reach your bodies natural potential. on some levels we will all be begginers but for the most part i think once you learn how to train effectively to achieve results wether they are minimal results or not i think that is when you have progressed to intermediate. a beginner doesn't truly know what their body is capable of and how to maximize its potential. a intermediate understands concepts of rep scemes and weight progression for obtaining results.