iCloud Drive was first announced at WWDC. This feature is Apple’s new approach to iCloud file syncing, replacing Documents and Data. The new interface acts more like Dropbox, with one central folder containing all iCloud documents in one place. This gives more flexibility over the model used by iOS 7 and Mavericks, where iCloud documents are siloed within their own app’s containers.
At WWDC, Apple announced that iCloud Drive could be accessed from Mac, iOS devices or even PC’s (as shown by the iCloud Drive preview page). However, a new setup screen present in iOS 8 beta 3, released earlier today, shows that Apple is also planning to expose iCloud Drive on the web. Although people were surprised by native PC support, bringing iCloud Drive to the web enables even more flexibility, bridging any OS with a modern web browser.