Skyhook powers location on tens of millions of devices worldwide and Skyhook's network processes over 400 million location requests daily. With that, Skyhook has build a pretty comprehensive WiFi and CellID database in North America, Europe, which should be appealing to Amazon. In addition, Skyhook is increasing its coverage in Asia and South America. The other options for Amazon is to use Navizon, or to build its own Wifi location service (WiFi probes collection on its devices; database, etc).
Skyhook might also offer its other technology to Amazon, specifically SpotRank, a data mining and intelligence service that predicts the density of people in predefined urban square-block areas worldwide at any hour, any day of the week. Amazon and its advertisers could use this behavioral intelligence data to serve highly targeted location-based content and ads.