How due dates & reminders work
If your status feed requires regular updates, most likely a due date has been set by the admin of this feed through the recurrence setting.
For example, a due date for a weekly status report can be set on Fridays at 3 pm or on Mondays at 10 am.
In this case all feed participants with "Can Update" permissions will receive an automatic reminder from status.net to post an update. Reminder will be sent to your email 2-3 hours before the update is due.