Dropbox is Killing It
They are quickly becoming the de facto network file system for mobile.
Check this out:
Apple should buy them. Like, immediately. How much would it suck (for Apple) if Google bought Dropbox? Or vice versa?
Apple might be able to wrest momentum back from DropBox if they made a MobileMe lite that was just ~2GB of storage, and gave it to all iTunes account holders. iPhone app user data should be by default synced to that storage (with opt-out).
(It's not as urgent for Google, as there is already some kind of network storage used by Android with over-the-air sync.)