You know what I'd like to see them do? Have a "growing storage" like gmail, as an incentive to sign up right now (so your dropbox storage starts growing right a

You know what I'd like to see them do? Have a "growing storage" like gmail, as an incentive to sign up right now (so your dropbox storage starts growing right away), and as a conversation piece to improve the viral nature (one more hook to tell people: "so it syncs all your files, and the amount of storage you have is always growing like Gmail).