Amazon has just announced a new update for its Kindle Fire tablet, with some key new security features regarding parental control.

With the new update, version 6.3.1, password protection can be applied to purchases, to the Silk web browser, and can limit access to certain libraries stored in the device. The update can be downloaded and installed manually, or users can wait for it to be automatically pushed to the device whenever a wifi signal is established.

Other features of the update include:

Sharing: Easily share favorite passages and notes from books directly from Kindle Fire. Simply highlight a passage and select “Share,” add a note, and choose which social network youd like to post to.
Book Extras: Powered by Shelfari, Amazon’s community of book lovers, Book Extras make it easy to see supplemental material about the book you are reading, without leaving the book. View descriptions of characters, a glossary of common terms used in the book, information on the authors and common locations referenced in the book, and more. To view Book Extras within your book, tap the bottom of the screen to bring up the options bar, tap the menu icon and select “Book Extras.”
Archive of Personal Documents: Your personal documents are stored in the Amazon Cloud and available for redownload at any time from the Docs content library on your Kindle Fire. Just as with Kindle books, Whispersync automatically syncs notes, highlights and furthest page read for personal documents.
Print Replica Textbooks: Students can buy thousands of print replica textbooks to read on their Kindle Fire and save up to 60% off the list price of the print textbook. Print replica textbooks maintain the rich formatting, color and layout of the print editions, with features including notes and highlights, zoom and pan, linked table of contents, real page numbers, and Whispersync of notes, highlights and furthest page read.
Reading View for Amazon Silk: With Reading View on Silk, the content that you’re interested in is elevated above the clutter in a reading-optimized, single screen view (even for multi-page articles). The full page is still available in the background, allowing you to easily toggle back to a traditional view to see other interesting features on the page.
Movie Rentals: The rental period for movie rentals downloaded to Kindle Fire now starts when you starts watching the movie, rather than at download.
Additional Enhancements: Faster re-connect of Wi-Fi after your Kindle Fire has been asleep, and general performance enhancements.

In related news, it was just reported that big box retailer Target will stop carrying Kindle tablets on May 13th, likely due to competition, with the tablets being a sort of merchant in itself, making the browsing and purchase of all things Amazon very simple.