The four hardware buttons — back, menu, search, home — are in different orders on different phones. The Nexus S buttons are in a different order than other Samsung Galaxy S phones — and in a different order than the Nexus One.
This is the sort of thing that epitomizes the difference between iOS and Android. Design is about making decisions. Those who prefer Android, I’m sure, don’t see this as a big deal at all — let “the market” determine in what order these buttons should be. Those who prefer iOS find it appalling — Google should have done the work at the outset of determining the one true order for these buttons.
Update: Andrew Wood has an illustration of the differences among Android handsets.
★ Monday, 6 December 2010