The OfficeTalk mail service is the default mail service for each user. This means that when other OfficeTalk users send mail to a particular user, the message will, by default, be sent using the OfficeTalk mail service. OfficeTalk lets you specify a different default mail service for any user.
For example, if a user is set up with MAPI as his default mail service, then any messages sent to this user from other users will be sent and received via MAPI. This is useful if organisations wish to standardise on a single messaging system, such as MAPI.
You may specify the default mail service for a particular user from the Services page of the relevant user's property sheet.
Select the appropriate mail service and press the Default… button. Press OK to save your changes.