With two days left before the end of the year, Amazon finally delivered on their promise to enable ebook lending on the Kindle Store this morning. You won’t find it on every title, but if it’s available then you’ll see a prompt in two places:
1. At the top of the product page for books you’ve purchased:
2. Under the “Your Orders” list of books on the “Manage Your Kindle” section of the Kindle Store:
As of this morning, very few titles seem to have the feature enabled. It appears that all titles without DRM (see this post for details) have it enabled, but the feature is much rarer on DRM’ed titles.
You can tell whether a book is lendable before purchase by checking under the Product Details section, 
where there’s now a new category named “Lending.”
As for the feature, it’s pretty much as expected and in line with what Barnes & Noble offers on the Nook–the loan period is 14 days, during which time you can’t read the title, and you can only lend a title once. So yeah, it’s not restriction-free lending, but more of an optional loan-once coupon you can redeem on certain titles.
Only U.S. customers can initiate loans, says Amazon. If you live outside the U.S. and you receive a loaned book, your ability to accept it will depend on what geographical rights are available in your area.
Update: Here’s a little more information regarding how lending works on titles, taken from Amazon’s Digital Text Platform (DTP) FAQs. Every book published through the DTP, meaning virtually every indie book, has lending enabled by default. However, on titles where the publisher is taking the 35% royalty rate–which is required on anything priced below $2.99, and optional on anything priced between $2.99 and $9.99–publishers can opt out of the feature. This means that not every DRM-free ebook will necessarily have lending enabled, especially after today. However, if lending was enabled when you bought the book, the feature can’t be taken away even after the publisher turns it off.
Amazon Kindle Lending [Amazon]
By Booksprung » Amazon’s new lending feature is probably going to anger some publishers December 30, 2010 - 10:40 AM
[...] that in mind, I have a feeling that some indie publishers are going to be up in arms about the new lending feature that was enabled this morning, because of how Amazon rolled it [...]
By Amazon’s new lending feature is probably going to anger some publishers December 30, 2010 - 12:09 PM
[...] that in mind, I have a feeling that some indie publishers are going to be up in arms about the new lending feature that was enabled this morning, because of how Amazon rolled it [...]
By Tweets that mention You can finally share kindle books with friends: Yay! Who wants to share? -- Topsy.com December 30, 2010 - 8:08 PM
[...] This post was mentioned on Twitter by Patrick LaForge, Karen Wise, Erin Nichols and others. Erin Nichols said: You can finally share kindle books with friends: http://tinyurl.com/2f7eosl Yay! Who wants to share? [...]
By Booksprung » Kindle users already forming community lending libraries December 30, 2010 - 8:56 PM
[...] are days when I love the Internet. It’s been less than 24 hours since Amazon rolled out ebook lending, and already there are at least four places online where you can lend and borrow Kindle titles with [...]
By Kindle users already forming community lending libraries December 30, 2010 - 9:49 PM
[...] are days when I love the Internet. It’s been less than 24 hours since Amazon rolled out ebook lending, and already there are at least four places online where you can lend and borrow Kindle titles with [...]
By Catherine December 31, 2010 - 7:10 AM
Check out the Kindle Lending Club page on Facebook – for people to request and offer Kindle book loans, discover great new books for free, and share their collection with other book lovers:
http://www.facebook.com/pages/Kindle-Lending-Club-Borrow-and-Lend-Kindle-Books/152751058110306
By Barbara Cundiff November 28, 2011 - 10:37 AM
Where can I learn how to lend and borrow books on my kindle
By Chris Walters November 28, 2011 - 12:33 PM
@Barbara: I’m not sure I understand. Do you mean you need something more than what’s listed in the post? If you have questions about borrowing Kindle-formatted ebooks from your public library, then just contact the library for assistance. In my experience, it’s just a matter of checking out the title through your browser, and then you’ll be presented with a button you can click that will take you to an Amazon download page.