Kentucky's geospatial data clearinghouse, Kygeonet, is a great example of a geographic information mart, offering a wide variety of data and maps as downloads or online applications. Recently KyGovMaps published a new page on the the site, one that leverages ArcGIS Online as a platform for delivering maps and apps, including iPhone/iPad apps. Here's the KyGovMaps site:
The site leverages the ArcGIS.com map viewer - a free, hosted application that's built into ArcGIS.com - and it's used to enable anyone to view a variety of layers from farmer's markets to landuse. It also leverages some of the template applications from the map viewer's template gallery.
I recently posted on the ArcGIS Online blog about how organizations can leverage ArcGIS Online as a platform for their map publishing and viewing needs. There's a number of things in the works that will be announced at the 2011 Esri International User Conference that will really make a difference for organizations, and potentially change the landscape of how people use maps and publish geographic information.