Each driver has a characteristic spatial and temporal scale at which it affects ecosystem services and human well-being. Climate change may operate on a spatial scale of a large region; political change may operate at the scale of a nation or a municipal district.
Amazon has several competitors in the electronics and general merchandise segment, many of which are brick and mortar rivals including Best Buy, Family Dollar, RadioShack, Staples, Target, Walmart, Sears, Big Lots, Delia and Systemacs.
In fact as Gizmodo astutely points out, the biggest competition for Kindle Unlimited right now might be Amazon itself. Current members of Amazon Prime can check out one book a month from the Kindle Owner's Lending Library (selection: more than 500,000).