Its like the NSA
No corporation will have the manpower or spend the money to actually monitor employees in real-time. Rather, like the NSA, the data will be stored somewhere, and when they want to fire you, they can go back and bring up every coffee-break and comment.
That's been the case for a very long time now. Ask any InfoSec professional about the data they're able to collect and correlate on any employee in the company. Browser history, keystrokes on your computer, mouse clicks, application based data, emails, chats, it's ALL captured and has been for a number of years now.
When they want you, they'll get you. Best way to avoid it: don't do anything on your business computer that's not directly related to your job.
Use your smartphone as a hot-spot and get a cheap tablet for any "personal" things you do while at work. Don't EVER use the company's internet for personal business, period.