The Internet has utterly transformed the ways in which we do research, not just on science, technology and politics, but also on literature. Using "Cliff Notes" as a source for quotes for your paper is a no-no, but using it as a jumping off point for your own searches on the Web is perfectly acceptable.
How does this work? Let's say, for illustrative purposes, that I wanted to do a paper on Mark Twain's novel, "Huckleberry Finn." I know that that's a huge subject, one much too large for my paper, but I'm particularly interested in exploring the relationship that develops between Huck and Jim as they ride the raft down the Mississippi. I could thumb my way through a copy of the novel, but an easier, and much faster way to find the scenes I'm interested in would be for me to use "Cliff Notes Online," which lists a variety of scenes for my consideration when I type in "Huck and Jim." Here's some I pulled from their web site:
http://www.cliffsnotes.com/WileyCDA/LitNote/The -Adventures-of-Huckleberry-Finn-Summary-Analysis-and -Original-Text-by-Chapter-Chapter-31.id-20,pageNum-3 23.html
*Book Summary, page 2: Huck and Jim encounter several characters in the book.
*Characters are listed who interact with Huck and Jim here.
*Chapter 12 and 13, Huck and Jim leave Hannibal.
*The con men take over the raft; Huck and Jim are no longer in control of their journey.
*Huck must decide whether or not to help Jim escape slavery, a key moment in Huck's character development.
*Tom arrives at the Phelps farm; he now controls the adventure of Huck and Jim.
After checking these and other summaries, I decide that those listed above fit the needs of my paper, and so I read those sections of "Cliff Notes" and my copy of "Huckleberry Finn." While doing so, I note any interesting key words and phrases for my later search online. I'll use them to find essays on those aspects of "Huckleberry Finn" I'm most interested in.
I'll use as an example of this research technique the key scene in "Huckleberry Finn" when, in Chapter 31, Huck realizes he must "rise above his principles," specifically his belief that if he engages in an act that abolitionists would approve of (freeing Jim), he would go to hell.
Here is how that scene is described in "Cliff Notes":
"As Huck ponders his choices, his conscience begins to trouble him again. He cannot help but feel guilty for assisting Jim, despite the fact that his instincts constantly force him into that role. After trying to pray for resolution, Huck writes a letter to Miss Watson detailing where Jim is and signs it Huck Finn.' After he finishes the letter, he feels momentary relief and is confident that he has saved himself from going to hell for helping a slave.
"Instead of being satisfied with his decision, however, Huck begins to replay their trip down the river. He reminisces about the two of them a-floating along, talking and singing and laughing' and cannot force himself to see Jim as someone disgraceful. Huck trembles as he again picks up Miss Watson's letter and realizes that the struggle must stop: He must decide forever between two things: heaven and hell. He pauses for a minute, then declares All right, then, I'll go to hell' and tears the letter to pieces. Once Huck makes his decision to betray society for Jim, he immediately plots to steal Jim back out of slavery."
By reading this summary in Cliff Notes, I gather the following interesting phrases: "Huck's choice," "Huck feels guilty," "Huck helps Jim," "Huck between heaven and hell," "Huck thinks about slavery," "All right, then, I'll go to hell," and "Huck betrays society for Jim."
I decide to run a search on this direct quote from the novel: "All right, then, I'll go to hell." Here are some results:
I found an essay by Susan Brassfield Cogan here:
http://www.socyberty.com/Spirituality/All-Right -Then-Ill-Go-to-Hell-Honoring-Your-Own-Morality.7681 9
In the essay, I not only found the full quote of the scene in question, which will help me if I want to use parts of it as quotes in my paper, but I also found some interesting ideas on the meaning of his decision. I could check this essay for more interesting search phrases, or include quotes from this essay in my paper, which I would then discuss, or do both. I opt to do both.
I then continue my search based on the quote I used earlier and find:
http://www.npr.org/templates/story/story.php?st oryId=4753976
An interesting essay on the subject in NPR's "This I Believe" web site.
http://www.mochamomma.com/2006/09/29/all-right- then-ill-go-to-hell/
A blogger who compares Huck's choice to choices made in "To Kill a Mockingbird" and "Les Miserables." I may want to take up points like that in my paper. I may want to think about those two works, or other works that deal with crises of conscience similar to what Huck went through.
http://books.google.com
I discover that there is a book that deals with these questions in Google Books, "Huckleberry Finn as Idol and Target." Would it be worth my while to get that book and read it for insights I could use in my paper?
http://www.ozdachs.com/enews/nl-060216.htm
This posting listed a minister's sermon on the quote. "When Mark Twain wrote these lines it marked a watershed in American literature, morals, and justice." A big claim. I could write a paper just on that point alone.
By now, I realize that Huck's crisis of conscience scene in "Huckleberry Finn" carries enough weight to serve as the theme of my paper. I really won't have to deal with other scenes in the novel in order to delve deeply into Huck's character.
So, I begin writing my paper, looking up answers to questions that occur to me as I write.
This may be a longer answer to your question than you would expect. But I think it's useful for any writer and scholar to know that you can use any material, even "Cliff Notes," in ways that don't involve any form of cheating. Think of "Cliff Notes" as tools for further research, not as a citation source, and you'll be fine.
My point is simple. Use "Cliff Notes" as a trigger to prime the pump of your own creative thoughts by helping you to find links to others' creative thoughts on the subject you're interested in. I guarantee that if you use this method, your paper will be original and genuinely fascinating. Why? Because you will be discussing points that genuinely fascinate you.