You know that big thingy of legalese that's called something like "Terms and Conditions" or "Terms of Use" or "Terms and Disclaimer"?? You have to sign one (or click "I agree" to one) every time you buy & use a new software or make a contract for internet services. They almost always say that you give your permission to have your data saved and monitored.

So yeah . . . they're monitoring you. Just, monitoring right now is pretty basic. They pick out key words you write a lot & they run them through a computer. They can't & don't have the technology to monitor most places generally -- that's why facebook and twitter (for example) make no warranty that you won't get harassed or threatened using their services & they don't take any responsibility to stop such behaviour unless you report it . . .