Let's Talk is a weekly feature at i swim for oceans.I have to say it really depends. There are good cliffhangers and bad ones. I think you should leave your audience wanting more, but tie up loose ends so that each book is a book in and of itself. Harry Potter is something everyone(nearly) has read, and there are cliffhangers that make you crave the next book, but the next book is not just a continuation of the book before. One book series that I thought had terrible cliffhangers, was the Possession series by Nancy Holder. The endings of these were extreme cliffhangers. I didn't so much want to read the the next book, but felt I had to read it so that I could finish book two or book three. There just ended in the middle of things with nothing being resolved. I don't think those are good cliffhangers.
Question: Cliffhangers - love them or hate them?
Across the Universe by Beth Revis on the other hand, especially A Million Suns, had fantastic cliffhangers. The books both wrapped up their story, but the main story line was still going and she gives you just a glimpse at what's ahead, so that you crave the next novel. So I'm a sucker for a good cliffhanger that has me dying for the next book, but I hate feeling obligated to read the next book, because the story never finished.