I have covered Amazon's navigational menus before (here, here, here and here). This is yet another update to Amazon's navigational menu: The Shop by Department still exists - and is still ordered the same way (preferencing digital over physical). But instead of being simple links, everything expands on the hover to showcase different product & merchandise depending on the category. Below you see two examples: Kindle (which highlights each model and Kindle related products / services) and Cloud Drive (which is a large promotion).
The plus is that there is more real estate and opportunity to merchandise and promote (for instance, the Cloud Drive unit is far more interesting and explanatory than a hyperlink). The negative is that this is a heavy series of interactions and can be a slow user experience.
Amazon is the king of conversions and monitoring pixels... interesting to watch what happens with this experiment.