eNotes is specifically aimed at students (from middle school to college) who require help with their school work. I see absolutely nothing wrong with any student accessing this website for new ideas for their class assignments, provided the student doesn't plagiarize the eNotes' editors' work. I have routinely suggested to my own students to use the website--with the warning not to use my own words or ideas and repeat them back to me--and I know many of them have benefited from using it. I, too, have gained new insight after reading the words of eNotes editors--both in the Q&A and Discussion sections.
Most of the editors who contribute to eNotes are teachers themselves, as you can see by looking at their profiles. They are offering an entirely ethical service intended to help students at all levels with their studies. There is nothing wrong with using any legitimate services to help you with your homework. That includes legitimate services offered on the internet. Your English teacher would probably approve of your seeking additional sources of information, provided of course that you are not presenting other writers work as your own. Ideas are common property. If your English teacher should ask about your sources of information, I think you should tell him or her precisely what those sources are. Most teachers these days are so busy that they are not able to give students much in the way of personal assistance, and they can understand why students look for outside ethical assistance. There are some services on the internet that blatantly offer to help students cheat--bur eNotes is certainly not one of them. The editors who work for eNotes are teachers with high ethical standards and wouldn't be associated with any service that was detrimental to education. If you look up practically any subject on Google, you will usually find links to eNotes right up at the top of the list. It has an excellent reputation and is used for scholarly research in many different branches of study.