"Privacy" means something very different in an age where anyone can look up anyone else online. You know that future and present employers can look at your social media profiles and learn everything from where you grew up to who you voted for in the last election.
As a result, hopefully, you curate your public presence carefully. Even once you've landed a job, managers and other higher-ups might still be doing some digging. But even if you're totally off the grid, social-media wise, there's a lot that employers can find out about you, once you're working for the company. Employee monitoring ranging from video surveillance to keystroke loggers lets companies know what their workers are up to at any moment of the day.
Legally, employers are within their rights to monitor workers (for the most part). But from a privacy perspective, this might give you, the worker, some pause. Has employee monitoring gone too far?