In what way? Is it that icloud has a better name? Or because developers actually use it?
Icloud makes your data available to all your devices, but the apps don't have to do anything with it. BackupAgent makes the data available to "an application that wishes to participate in the backup and restore mechanism", but the app doesn't have to participate (and they tend not to). It lets you sync settings across android devices as well as back up.
It's API level 8, which is OS version 2.2. Cloud sync was from day 1. Remember, Google has basically no desktop apps, so as soon as something is synced on your phone and available in a browser it's done what icloud does. So it's not hard to see where the idea came from, but Apple's control over the hardware and software means it has a much wider applicability, and a desktop/web api makes sense on Apple where it doesn't on Android (why would your Android mp3 player sync playlists when the developer doesn't have a desktop version and you're not firmly pushed towards using it even if they did?). All in all, Google's inventiveness gets no attention.
Apart from Twitter, I can't think of anything on my Android which should be cloud-synced with my desktop and isn't already. Twitter wouldn't need an OS-based service to sync my position in my feeds though.