It's been a busy day for Amazon, with announcements about its voice tech efforts and, wait for it, a Treasure Truck that offers on-the-go deals to people. But there's more where that came from. If you use Kindle for Android, you'll now notice the addition of some handy sharing features to the application. In this new version, released today, you can start sharing book quotes with friends across social and messaging platforms, such as Facebook, Twitter, Google+, Hangouts and over text or email. Most importantly, thanks to what Amazon's calling Instant Previews, people who don't have the app installed are able to read a free preview of the book you're reading -- directly from a smartphone, tablet or desktop computer. Amazon says that feature works seamlessly, since it doesn't require anyone to sign up, sign in or to have the Kindle application on their device.