Check the fine print before plunging in; Amazon Kindle books, for example, may only be loaned once (and many can’t be loaned at all; it’s up to the publisher)
The lending sites' founders say they are helping publishers because their users, after borrowing books, can purchase other books in the same series or by the same author.
"People are saying I borrowed a book and I bought it because I didn't finish it," said Jeff Croft, who created Lendle. "That seems to be happening a lot."
The online lending sites have cropped up as e-book and e-reader sales have soared. Consumers spent $1 billion on e-books in 2010, and that number is expected to triple by 2015, according to Forrester Research. It added there were around 10 million e-readers in circulation in the U.S. at the end of 2010, nearly tripling the 3.7 million at the end of 2009.