How many people wrote comments for the question "Any additional notes or comments."?
question refers to questiontext; wrote comments refers to AnswerText(QuestionID = 103) ! = -1
SELECT COUNT(T1.UserID) FROM Answer AS T1 INNER JOIN Question AS T2 ON T1.QuestionID = T2.questionid WHERE T2.questiontext LIKE 'Any additional notes or comments' AND T1.AnswerText IS NOT NULL