Please list the username of the current official Facebook presence of all the current legislators that are famous or impact.
username of the current official Facebook presence of the legislators refers to facebook; legislators that are famous or impact refers to wikipedia_id is not null;
SELECT T2.facebook FROM current AS T1 INNER JOIN `social-media` AS T2 ON T1.bioguide_id = T2.bioguide WHERE T1.wikipedia_id IS NOT NULL GROUP BY T2.facebook