What do you think about a digital assistant made by the NSA, for example for people with dementia?
It would be accessible everywhere and it would know everything
and it could result in some nice dialogues:

>> "Okay NSA?"
"Yo, I'm always listening."
>> "I forgot to take some nice pictures from my last vacation, do you have some for me? D:"
"Of course, here ya go."

And you could even trigger it without a keyword.
>> *Walks to the fridge*
"Hey, you've already been at the fridge 45 minutes ago and since then you haven't bought anything."
>> "Thank you NSA"