IIRC, Android sort of does what iCloud does, but iCloud is very different and IMHO a much better offering from a developer perspective. According to Apple’s website:
iCloud Storage APIs enable your apps to store documents and key value data in iCloud. iCloud will wirelessly push documents to a user’s device automatically and update the documents when changed on any device — automatically.
iCloud allows an app developer to treat the cloud as a natural extension of the iOS device. In-cloud storage is almost as easy to use as saving data locally, and you get push synchronization for free.
This is similar to Dropbox, but baked right into the system APIs. I don’t think there is anything like this in Android. You of course can hack something using Google Storage API or Amazon S3, but they are very different beasts from iCloud: while iCloud associate the storage with a user, Google and Amazon associate it with an app. That difference has a huge implication. iCloud makes it trivially easy to synchronize data for one app across devices of the same user. To achieve the same thing with Google and Amazon’s offerings, you would have to provide your own code to identify user, isolate data of different users in the cloud, and bring in your own synchronization/push magic. On the other hand, if you want to mine across data of all users – answering questions like the most-bookmarked pages – then you might feel iCloud’s extra layer of abstraction getting into your way.