Most applicant tracking systems hold many people who applied before and were not hired, often because someone else was chosen or the role closed. Talent rediscovery searches that history when a new role opens, then re-screens matching people against the new requirements. For example, a runner-up for a team leader post last spring might be a strong fit for a similar role at another site today.
Rediscovery makes use of investment already made in attracting and assessing candidates, and past applicants often respond well to being remembered. It should use the new role's criteria, not old scores, because roles and candidates both change. Checking that consent and retention periods allow the contact, and giving everyone rediscovered the same screening as new applicants, keeps the practice fair and compliant.