Allows monitoring of Emails sent, there's a number of filtering options.
Immediate send and resend of emails.
This would be a configuration screen, in this context you use this to configure your Email Inbox.
Hope this helps
Transaction SOST is used to view the status of the sent mails from SAP.
You cna filter the mails sent by a particular user, on a specified date range and time.
You can list the mails in the status Waiting, Error, Sent or Transmitted.
You can also go to the log of the mail and see its details and can also open the mail sent by the user.
You can add the filters as per your requirement.
Transaction SCOT is SAP Connect used to make connections from SAP to external applications.
You cna configure sending of external mails in SCOT by specifying the SMTP host and port to be used.
Hope this gives you a basic idea of the 2 transactions.