Implications of “Mashup” JavaScript API for ArcGIS Server

As more and more of the “good stuff” for GIS serves developers it’s getting harder perhaps for users and their managers to understand the implications. Programmable Web does a nice job explaining ESRI’s new ArcGIS JavaScript API that supports via extensions Google Maps and Virtual Earth.

What’s hidden below, perhaps, is the rest of the story: that this may be one of the compelling selling point for ArcGIS Server. From the article:

With the release of this API, ESRI has ventured forth to make the integration of GIS web services much more accessible to the general public. There is one catch, however. Unless you or your organization have implemented ArcGIS Server 9.3, you will need to rely on other implementations of ArcGIS Server that have been exposed as RESTful web services. This means that to truly integrate GIS functionality customized for your own needs, you will need to have access to your own ArcGIS Server instance.

Will this further encourage Server uptake? Will it prompt ESRI or (if possible via ESRI’s licensing) third-parties to provide hosted ArcGIS Server instances?