I put a spoiler tag just in case anyone hasn't read 1984. I know some schools actually assign the book for reading. (From a book quality stand point, I really don't understand why.)
There were many parts of the book that simply were not explained. But baring Magic Realism (Where subtle magical elements take place, that doesn't call attention to itself) one would almost have to assume electronic telepathy, which can be believable of they actually expanded on the primary technology being allowed being the surveillance system. Even as magic realism (which it's not), reading thoughts in my opinion in this fashion is far to overt.
Now in terms of actual horror, some people might say the lack of explanation makes it scarier. But I honestly know of another author that provides better explanations for his science. Even though the author's science may be inaccurate in parts in Neuromancer, at least some sort of explanation was given within the stories context. Though it's not stated as "Big Brother is watching you", but rather your simply left to infer the dystopian state through character interactions and subtext instead. The difference would between:
(1. Big Brother is watching you.
(2. The Turian was a genetically restored person that was switched into a killing machine, Sometimes he would take bribes. It could range between excepting monetary compensation, and exchanging freedom for a prostitute.
Even in number two, this would not be perfect as I would personally prefer to see the Turian excepting monetary compensation, and how he feels about that aspect of them self. I know number two could be something that's more easily fixable. Though the exception might be if one were writing short fiction. Sometimes in short fiction if you want to keep it short, you have to tell in some parts.
"Big Brother is watching you" on the other hand is extremely vague, and almost borders on telling instead of showing. I'm sure I'll find other things over time. But for now this is my conclusion.
I went ahead and put spoilers, but I tried my best not to spoil to much.