1. A content delivery network (CDN) including a plurality of physical resources, said CDN comprising: a single autonomous CDN partitioned into multiple virtual CDNs, said multiple virtual CDNs being organized into a CDN hierarchy, and said multiple virtual CDNs having at least some overlap, each virtual CDN of said multiple virtual CDNs being allocated separate physical resources of said plurality of physical resources, wherein at least one virtual CDN has at least one dedicated content delivery (CD) service selected from the group of CD services comprising: cache services, rendezvous services, collector services, reducer services, and control services, and wherein operation of at least one CD service in said CDN is based on control information received from a control service in said CDN, and wherein, within said CDN hierarchy, at least one parent virtual CDN has at least one child virtual CDN, and wherein said at least one parent virtual CDN grants at least one privilege from a group of one or more privileges to said at least one child virtual CDN, wherein said group of one or more privileges includes: authority of the at least one child virtual CDN to use CD services inherited from the parent virtual CDN, and wherein said at least one privilege granted to the at least one child virtual CDN is subject to one or more of: (i) expiration, (ii) revocation, and (iii) renewal, and wherein, when a first service in a child virtual CDN in said CDN hierarchy issues a request to a second CD service in a parent virtual CDN in said CDN hierarchy, said parent virtual CDN is configured to either: (i) handle the request, or (ii) proxy the request to another CD service, or (iii) redirect the request to another CD service.