Microsoft Knowledge Base Article 902196 contains the following introduction:

The Application Experience Lookup Service is a new service that was introduced in Windows Server 2003 Service Pack 1 (SP1). This service is part of an infrastructure that automatically applies software updates to programs to make sure that they run on newly released service packs and newly released versions of the Windows operating system.

Note Windows Server 2003 SP1 is included in x64-based versions of Windows Server 2003.