Improvements the new 2.5 firmware will bring to the Kindle include the following...
* Collections: Organize your books and documents into one or more collections.
* Password Protection: Password protect your Kindle when you're not using it.
* Facebook & Twitter Posts: Share book passages with friends on Facebook and Twitter directly from your Kindle.
* Popular Highlights: See what the Kindle community thinks are the most interesting passages in the books you're reading.
We'll post another update when we find out more details, or when we have an exact date for launch, but expect it at the latest by the end of next month.
Via: The Digital Reader