The flag indicates whether or not the Feedback entry will affect the user's Feedback score. Only feedback left by verified users can count toward the aggregate score of another user. If a unverified user leaves a Feedback entry, then later becomes verified, that Feedback entry will still have no affect on the recipient user's Feedback score. Or, if a user is verified and at some later date changes to unverified status, the Feedback entry left while the user was verified remains in effect.
See the
Field Index to learn which calls use Countable.