How does technonlgy affect the Party's ability to control its citizens in "1984"?

The Party uses two-way
telescreens to spy on
people.  The telescreens are positioned in people's homes, as described in

Part 1, the first few chapters, so that most of the area is visible to the camera.  This
gives
people few places in which they have privacy.  The Party shows
programming on the telescreens
such as exercise programs and politicalbut it
also can see into the rooms.  The telescreens
aren't just in people's homes;
they are everywhere such as restaurants, bars, any place where
people might
be.  Additionally, there are hidden microphones and people never know when
the
Party might be listening or watching everything said or done.  Even if no
one is currently
watching or listening, the people don't know when the Party
might be and they have to assume
that they are always under surveillance. 
This constant fear of being watched allows the Party
to control the
population.  People see enough instances of others being taken away by the
Party,
never to be seen again, to have cause to constantly worry about their
own well-being. This fear
makes the people easy to
control.