Not to pile on or anything, because that phrase seems to have touched a nerve - but, I don't mind helping other people at all. I do mind when I spend 8 hours at work helping other people, and don't have time to complete the work that I was actually supposed to be doing, and then get criticized for not getting the work I was assigned to do done. It doesn't help to err in the other direction, either, though - once everybody knows that you know how to do "x", even if you're swamped with other work, you can't turn them away, or it'll haunt you on your next performance review. Hence the article's original advice: never let anybody know you're good at "x".