For example if I had a "date" field (d = day digit, m = month letter, y = year digit) I could restrict entries to dd-mmm-yyyy instead of any number of different entry types(e.g. dd-mmm-yy or mmm-dd-yy or etc.) a user might enter.
A real life example using above entry types: User "A" creates a new feature in a feature class and in the "date_created" field user A enters 01-JAN-2015. User "B" creates a new feature in the same feature class and in the "date_created" field user B enters 01-JAN-15. User "C" creates a new feature in the same feature class and in the "date_created" field user C enters JAN-01-15. These are all valid entries for a "text" type field and 100% accurate for the date but it is incredibly frustrating to SQL. To prevent this I am hoping that ESRI file geodatabase or feature classes have input mask capabilities like Microsoft Access does. Below is an example of input mask for access database.
I am using ArcGIS 10.2 for Desktop.
