Repetition, even in graphic design, is okay, I promise. It's the way human beings learn. The perception is that if something is included on the page once, especially in an obvious fashion, there's no reason to repeat it elsewhere.
In this blog post by a Microsoft developer, there are examples of scrolling on a single webpage by moving left to right (vs. scrolling up and down). Also, some main navigational buttons and menus are now on the RIGHT side of the layout instead of the long-used left side of the layout location for these elements.
I believe this is an example of the influence of touch screens on tablets, phones, and computers affecting the long held paradigm of left side menu navigation. The gesture navigation of touch screens is making another mark on design and layouts.