This is a service that has been rumored to launch since 2009, but until now no luck. But it seems Google may be finally getting close to launch their rumored "Google Drive" in the coming months. So what can we expect from such a service?
At this point it's anyone's guess, because they could do a lot of things with it. Some expect it to become a Dropbox competitor, as in helping you transfer your documents from one platform to another, but offer you a lot more storage for free and also for a cheaper price if you need a lot of storage. Of course if they went this route they would have to offer the Google Drive on every platform, including iOS, and also Windows, Linux and Mac.
The other idea would be to work more like Chrome Sync, or iCloud, where they try to sync all the data you have on your Android phone to Google's Cloud: apps, app data, settings, pictures, videos, music, and even passwords. So you can sync everything to Google's Drive if you want, and then if you install a new custom ROM for your phone, or you're just buying a new phone, you can restore everything inside the new phone. Of course you might need to have a certain version of Android for some to work (like settings), but for most of the things I said, it should work on all Android devices.
The Google Drive name does imply that there is some kind "files in the cloud" service, so it might be both – a service like iCloud for Android users (but much more advanced) and also a service that syncs your files between many other platforms.