Amazon has just released a new firmware update for the second generation Kindle Paperwhite. One of the big enhancements is for the PDF experience and now users will see a small preview pane on the top lefthand corner. This helps orient you when you are pinching and zooming, to insure you know were you are in the document.
When you buy physical books from Amazon, you normally have to wait a few days for it to be shipped out. Now, whenever you purchase a book, the sample eBook version will be automatically added to your library, so you can read the first few chapters.
Finally, Amazon has unveiled cross platform syncing on the last page read. This has been on their Android and iOS apps for sometime, but is now available additionally on the Paperwhite 2.