Amazon has announced upgrades to its Kindle e-book reader, aiming to head off competition from the Apple iPad and Barnes and Noble's Nook.
The online retail giant, which launched the Kindle in 2007, has released major updates for both Standard and DX versions of the Kindle 2.5 firmware.
The biggest innovation is a link-up with social networking site Facebook and micro-blogging service Twitter, which will let Kindle users share passages from their e-books with friends.
The update, has already been sent to selected Kindle users, includes amongst other features include sharper fonts, two new font sizes, tools to sort book collections and password protection.
A full release is expected later this month, when updates will be sent to all via automatic wireless connections.
The Kindle, which was the first mainstream operating ebook reader, is facing some serious competition from Apple's iPad which has already reached one million units sold worldwide a mere 28 days after it was launched.