Cliffhangers, by definition, are when a story comes to an end where the main character(s) are, more often than not, figuratively hanging over the edge of a cliff. They (and WE) are left in a stressful situation where something is about to go down.
I think with all the competition out there to snag readers' attention and bring them back for more, some writers are turning to the Cliffhanger ending for help . . . and I think that could be a huge mistake.
What works in television doesn't always work in written fiction. TV is relatively mindless, whereas reading requires a certain level of imagination and time commitment. And, in general, readers need SOME closure at the end of a book as a payoff for that committment.
Now, I think the vast majority of readers are comfortable with what I call the Unfinished Business ending. Where you get to the end and realize that while some big questions/issues the MC faced have been answered/resolved, the result has brought forth more questions that need to be dealt with. BUT, in the Unfinished Business ending, most (if not all) of the initial story arc has been dealt with or resolved...and while the characters still have more business they need to take care of, they (and more importantly the reader) are at a comfortable stopping point.
To use an example most have read: The Hunger Games -- When the book comes to an end, Katniss has survived the Hunger Games and gets to go home a victor. But, to those who've read the book you know there are a ton of things still left unresolved. Her relationship with Peeta being a big one...and what, if any, effects will her "breaking of the rules" bring down on them all. But, for the time being, everyone is safe and on their way home to deal with the aftermath in their own private way.
The Unfinished Business ending gives readers something to think on. Gives them something to ponder while they wait for the next book to come out. And if you've given them characters they can fall in love with, they're going to want to come back for them alone.
But if you end the book on an actual Cliffhanger (I won't name any specific examples, but feel free to in the comments, if you'd life), where you leave the characters in some sort of imminent danger and/or throw a brand new danger that you don't plan to explain until the next book...you run the serious risk of making your readers feel like they're being jerked around, and having them avoid the very thing you want them to come back for. The sequel.
What do you all think: Do the obvious cliffhangers bother you? Do you actually like them? If you hear that a book has a cliffhanger ending are you less likely to buy it until you know the sequel is about to be released? Tracy wants to know these things.