puede hacerlo fácilmente mediante una declaración de caso:
SELECT SUM(CASE WHEN FACEBOOKID IS NULL THEN 1 ELSE 0 END) AS NbUsers , 'NO' AS FACEBOOK
FROM USERTABLE
UNION ALL
SELECT SUM(CASE WHEN FACEBOOKID IS NULL THEN 0 ELSE 1 END) AS NbUsers , 'YES' AS FACEBOOK
FROM USERTABLE