In what ways can taking a gap year be harmful to an applicant?
Gap years should not only be viewed as a means of enhancing one's college application, but also -- and more importantly -- to have a period of time dedicated to meaningful out-of-classroom experiences that encourage personal growth. Not engaging in some sort of meaningful activity -- be it work, volunteerism, cultural exchange, travel, or some other form of learning through doing can ultimately be detrimental to your college application. If you don't want to go to college immediately, but you also don't want to do anything else in the interim, I would not even consider that a gap year. I would call it time off. Conversely, a gap year should be considered "time on," and you should be able to speak or write about it as such during the college application process.