Answers:
A telescreen is a tv in the citizens homes where the police are always surveilling them.
It's different from what our tv's do because we can see the tv but no one can see us through it.
Yes, there are new technologies that would allow that. Being able to ask "Siri" questions, for example.
It could be meant to be used for that purpose but I doubt any terrorist or criminal have it in their house. Not no mention is a huge way of breaching one's privacy.
No. It would invade everyone's privacy and it would mostly be on common people's homes.
