As mobile phones and tablets grow to be the dominant way people access information there is an extra set of information that applications on these devices can take advantage of. Location, acceleration, direction (compass, gyrometer, inclinometer), ambient light and geofence monitoring. All of these can easily be taken advantage of using the Windows.Devices.Sensors namespace in WinRT.
This should get your mind buzzing with potential ideas like foursquare, FindFreeWifi or FindMyWay.
With all the great devices coming out and the super easy to develop for platform, Windows 8 is becoming a powerful tool for companies to provide location based services and visualize spatial data (stored in Azure and maybe using Hadoop. You know because its Big Data and all) and for entrepreneurs to create new compelling experiences with augmented reality.
To help you along here is a great free eBook with code samples, VB included!