Web interface! (major omission these days)
Quick example... iCloud.com gives access and edit-ability to users data (contacts/cal/mail/iWork) via its online interface. And web interfaces are basically becoming de rigueur for most apps now.
I'd really love to be able to access my TapForms databases stored online and using an online interface of some sort.
(and before you get the NSA nay-sayer brigade chiming-in... yes, sure, some may not want to use it for whatever reason, but at least it'd be an option for the majority that most certainly would!)