Oh...and don't be afraid of NULL columns!
It makes much more sense to have the [b]emailNotified[b] column there be a NULLable column that to have to provide an ugly '0000-00-00' fake date value!
It's faster to test a NULL value, too.
SELECT * FROM table WHERE field IS NULL
is going to be a lot faster than
SELECT * FROM table WHERE field = '0000-00-00 00:00:00'
The latter is really ugly.