When you no longer need to follow-up on a message, you can clear the flag and reminder or mark the message as complete.
Change the sound that plays for Outlook reminders.
Add a reminder to email messages for recipients or yourself.
Outlook 2013 - ignore the reminder dialog box;hit snooze;delay a reminder 5 minutes;Remind me later;Close the Reminder dialog box;
Reminders alert you visually and with sound to Outlook 2010 messages, appointments, meetings, and tasks.