People's sex lives & infidelity will be easily revealed.It's been a long time since I read it, but I'm pretty sure I was, too.
Also, everybody's crimes / atrocities will also be easily revealed.
This is why regulation & control over the technology would be important to not let it wreck society.
Also, Omni-Directional Sensors & Micro-Worm Hole Jammers would become very important for people if you had Star Trek level tech.