Using this system, a user connects to a mail server to retrieve and download e-mail. Then, the users can process the mail on the local client. Once the user is finished with the messages, the user once again connects to the mail server and uploads any changes. With this model, the mail server acts as the main repository of the user's e-mail. The disconnected model's strengths are that users can access e-mail from a variety of clients that have access to the mail server.
Users can also process mail offline.
This also translates to a shorter server connect time. However, the model does require a sufficient amount of resources on both the server and the client.