I remember reading stories a few years ago about how facebook employees used to spy on love interests. I'm sure there are better access controls in place these days, though.
However, if anyone at google or facebook gets caught doing that, it will have a hard time finding a job. At the NSA is probably encouraged behavior and I'm pretty no one is loosing his job over spying someone there, it's what they do after all.
These corporations, to my knowledge, have never used their data to:
* Spy on love interests
* Kill people abroad unilaterally
* Construct court cases against people
* Imprison people for victimless crimes (or any crime for that matter)
* Add me to no-fly lists
* Forcibly extract money from me to make me pay for their programs