Pro tip: you can block your boss from seeing a Facebook post.

Your rebuttal

Fair rebuttal? What I do with it on my break is my own business.

Also, I discovered this after I got home.

My work used to have a policy avainst using the Internet or company resources for non-work related activity. They have since relaxed that policy and even created a special WiFi system for personally owned devices to use at work.

Perfectly fair rule, imo; they're paying the bill on the internet, it should only be used for whatever they see fit. Just like if they're paying you, you shouldn't be dicking around on your phone. However on a break you're technically being played to do anything other than work. And THAT is fair game :)

It would be funny if you posted on her fb post, "please see me in my office Monday"