Answer
ArcGIS employs various caching mechanisms throughout the system to improve the performance and functionality of specific applications. Since Desktop, Server, and Mobile applications have different requirements, and caching improves different aspects of their functionality, various caches are not compatible across the system.
For example, Mobile ADF cache is used to store vector features and raster layers retrieved from the server and stored in a client side database. Such data is readily available to Mobile clients for local drawing, queries, and editing, even if the connection to the server is no longer available.
Server Cache is used by Web applications and its purpose is to expedite map image delivery from the server to client applications. Server caches also consist of pre-generated, rasterized maps, stored as images for different zoom levels.