Deferred action is when Immigration uses its discretion to grant certain individuals temporary protection from deportation. Deferred action allows a person to apply for work authorization and thus obtain a social security card and a valid driver's license.
Deferred action does NOT grant legal permanent residence nor does it grant Citizenship. Deferred action does NOT forgive unlawful presence in the US. These things are very important to understand. Anyone who thinks they qualify for deferred action should consult with a knowledgeable immigration attorney so they understand their rights prior to applying.