Amazon have released a new Kindle reader ... for the cloud.  Written to use HTML5, it provides a complete Kindle reader application entirely in a browser, supporting Chrome, Safari, and [of course] IOS' Safari.  (Not Firefox yet - HTML5 incompatibility?)  Presumably it supports the Android's browser too; not sure.  The experience is amazing because it's exactly what you expect:

But there are some interesting wrinkles.  First, because it's a web app, it can be updated infinitely without your involvement.  As of 8/11/11, it doesn't support highlighting, but if Amazon adds that tomorrow, we'll all have that capability without doing anything.  Second, it has *all* of your books available, all the time.  There's no interplay between "books on the device" and "books in the archive"; they're one and the same.  And third, you get the same user experience on every device; some would argue that's not a plus, but to me - someone with a PC laptop, four Macs, an iPad, a Palm Pre, a Motorola Droid, and an iPhone - it's a big plus.

Most cool of all; it can store books offline.  I'm not sure how this works - have to dig into this further - but if you're reading a book and you get on an airplane, lose your cell signal, or otherwise go offline, you can keep reading.  That's a pretty interesting feature for a web app, and one we may see replicated on other sites soon.

BTW a common online take is that this is Amazon's response to the new Apple App rules, wherein an App cannot link to a website (and hence, Kindle readers cannot just click over to the Amazon store).  I think that's a pleasant coincidence, and Amazon have been working on this capability for a long time.  I suspect they want to get out of a world where they have a separate client App for every platform.