Amazon Now Offering E-Book Lending Via Kindle
According to Amazon, only select eligible e-books are able to be loaned out, and just once for a period of 14 days. At least the owner doesn't have to own a Kindle; they can also use Kindle for Mac, Kindle for PC or any of the Kindle mobile apps. The publisher or rights holder can opt to not enable lending, and obviously not all are encouraged by the idea. Another interesting fact: the lender will not be able to read their book while it's loaned out, just like in a real-life, physical book situation.
It remains to be seen how many books will become eligible for lending, but hopefully it'll be quite a bunch. B&N has stated that around half of their books can be lent. Amazon, your turn.