Amazon may not be rolling out its Kindle 2.5 update until later this month, but the folks at Ars Technica have already managed to get their hands on it, and they've kindly shared a few impressions. While the added social networking capabilities may be the most standout feature, Ars found the new "Collections" feature to be the most substantive part of the update, as it finally gives you a way to manage all your books into groups that are more easily browsed than one big list. Those social networking features do seem to welcome additions as well, however, albeit with a few limitations -- while you can easily share a passage from a book with your Twitter or Facebook friends, it's delivered in the form of a link rather than an actual quote. Other new features like password protection also work just as you'd expect, and there's a number of more minor but pleasant surprises -- like being able to pan and zoom in PDF files. Hit up the source link below for a closer look.