Source : Free On-Line Dictionary of Computing

virtual point of presence
     
        (virtual PoP) A point, via which users can connect to an
        {Internet access provider}, which is not operated by the
        provider.  The user is charged by the telephone company for
        the call to the virtual point of presence which relays his
        call via some third party circuit to the Internet provider's
        central location.  This is in contrast to a physical {point of
        presence} (PoP) which is operated by the Internet provider
        themselves.  The advantage of a virtual PoP is that the
        provider can keep all their {modem}s in one location, thus
        improving availability and maintenance, but users do not have
        to pay long-distance call charges to that point.
     
        (1994-12-13)