Electronic messages are used to request, accept and decline sharing resources. A PIM may be used to generate the sharing messages. A user can accept or decline a resource sharing request (e.g., to share access to a calendar, a contacts list and a tasks list) by selecting an option within the electronic message. In particular, a sharing message can be sent via e-mail which sets permissions for others to view a user's information. The sharing message may include a reciprocal sharing request. The sharing message can include both a statement that the initiator is sharing data as well as a request to allow the initiator to share the recipient's data. A sharing protocol is defined that relates to establishing and managing a sharing relationship between clients and sharing providers. A sharing infrastructure is includes a framework for sharing.