1. A computer-implemented method for mediating user access to services over a network, the method comprising: maintaining on a service network host a registry of a plurality of services offered to a plurality of users over the network, the registry of services including a descriptive representation of the plurality of services, wherein the services are offered by entities independent from the service network host; maintaining on the service network host an association between a plurality of connectors and the plurality of services; responsive to an instruction, creating a first connector configured to communicate with the first service, the instruction indicating a first format for receiving messages at the first connector, the first service being configured to receive messages in accordance with a second format, and the first connector being configured, in accordance with the instruction, to translate received messages from the second format to the first format; and providing, from the registry to a user over the network, specifications for using the first connector to interact with the first service over the network.