This is a test of how screen readers announce navigation landmarks, prompted by an apparent bug in VoiceOver in iOS.
This section is marked up with role="complementary", and VoiceOver in iOS 5 announces it with "Landmark start". So my conclusion is that VoiceOver in iOS5 recognizes landmarks, but does not announce their names. If an aria-label is present, it will announce that. This suggests that we should always use aria-label, even if the function of the landmark is obvious given its role. However, doing so creates a lot of extra verbiage in JAWS since it announces both if both area present.
Also, the behavior of VoiceOver on iOS5 does not hold true on <nav> elements. Even if an aria-label is present on a <nav> element, VoiceOver does not announce it. This suggests that we should avoid adding ARIA landmarks to <nav> elements. In the case of a menu such as this one, I recommend adding role="navigation" and aria-label="Main menu" to the <ul> element. Notice that I'm not using the word "Navigation" in the aria-label—this is to avoid redundancy in JAWS.