This presentation will discuss enterprise web mapping and mobile applications that we've been developing for large utilities and communications companies, based on a number of open source geospatial components, including PostGIS, MapFish, GeoServer and Leaflet. It will discuss development of offline mobile applications using both PhoneGap to compile to native applications on Android, iOS and Windows, using a SpatiaLite database, and also use of HTML5 offline storage. We will discuss ideas on how to create extremely easy to use but still powerful applications, using approaches inspired by consumer web mapping sites rather than traditional GIS. The presentation will not be deeply technical but will include material of interest to developers as well as end users and managers.