The new version is embeddable across the web, and also acts as another revenue stream for members of the Amazon Associates Program. Online publishers who refer people back Amazon through an embed of Kindle for the Web will be entitled to a percentage of any revenue generated off of the referral.
Although it is limited solely to first chapter previews, Kindle for the Web functions largely like other iterations of the Kindle platform, as seen here:
KindleReader.LoadSample({containerID: 'kindleReaderDiv', asin: 'B003X28734', width: '640', height: '496'});
We're a bit surprised that Kindle for the Web did not come sooner. In addition to its popular Kindle e-reader, the world's largest online retailer currently has supporting apps for every major mobile platform, as well as desktop applications for PC and OS X.
Although the web service supports only book previews, it is clearly extendable to full titles. The question is how long Amazon will wait before flipping the switch to allow full content access through Kindle for the Web.