Add A Reminder Button With Posted Text Message
At present you have few options for each posted and received message such as
How about adding an option of REMIND ME or REMINDER?
Once a user clicks on it, it will give them an option of setting up a reminder for them to either follow up, etc.
At the time of that reminder, the content of the message will appear or at the time of setting up reminder allow the user to key in something in a message window for their own purpose.
A FLAG WITH DIFFERENT COLORS WILL BE GOOD ONE TO ADD.