本来的题目想叫ArcGIS Explorer，ESRI的google earth?但觉得不合适，explorer是古已有之的东东。新特点在于ESRI的地图服务，可以叠加自己的地图数据，可以以插件形式增加自己的功能（？）。其实更关注的在于其Server端的Web服务的发布能力（所谓ArcWeb Services ），以及这样的Service的开发能力，即是否可以使用这个服务开发自己的产品，数据能否更新还是只是显示。
好的概念还要好的产品，关注ing。
下面是David Maguire （ESRI Director of Products http://gismatters.blogspot.com/）的Blog原文。
ArcGIS Explorer - how it works
ArcGIS Explorer is a .Net desktop application based on a new lightweight ArcObjects library. The application is downloaded once from the server and installed on the local machine. It's best not to focus too much on the desktop client because the server is the most important part of the system.
Upon start up the client automatically makes a web services connection to a set of ESRI ArcWeb Services globe services. The web services are powered by ArcGIS Server 9.2. A new set of explorer services has been added to the Server core so that anyone (with ArcGIS Server) will be able to create and publish a service. It will also be possible to view ArcIMS and OGC WMS services. As you navigate around the globe, page views are streamed across the web to the desktop application for rendering. All the tasks (mini-applications) are server resident and are called from the client.
Right now we are busy loading data into the server. We plan to provide a set of free base mapping services (imagery, terrain, streets, points of interest) and location services (gazetteer, geocoding, reverse geocoding, computer finder based on IP address, directions, etc.). We will also provide some more detailed and specialized services for a fee. Basically, the plan is that if we have to pay a lot of money for data/services then we will have to pass this on to users.
ArcGIS Explorer – geographic exploration system
At the ESRI European User Conference in Warsaw, Poland this week ESRI unveiled our new geographic exploration system. The design goals of ArcGIS Explorer are to provide an easy to use application to explore global geographic databases. ArcExplorer is part of the ArcGIS family. It is a lightweight desktop viewer (less than 15 MB) that connects to geographic web services. The web services are powered by ArcGIS Server. Initially, the web services will be provided by ESRI using the ArcWeb Services delivery technology and brand. In keeping with our general strategy eventually anyone with ArcGIS Server will be able to create a web service for use by ArcGIS Explorer, or any other ESRI or open client for that matter.
With ArcGIS Explorer you can fuse data from multiple servers (OGC WMS, ArcGIS Server, and ArcIMS) and overlay local vector and raster data sets. The task-based interface allows fast visualization of massive 2D and 3D server-resident global terrain, raster and vector databases. The user interface exposes additional tasks for navigation, routing, geocoding/reverse geocoding.
It will be possible to personalize and customize the application by authoring new tasks that plug into the viewer and the server. We anticipate a Beta release in a few weeks time.