Of all the large companies that are now large internet players, do anyone particularly scare you in terms of how you data and track could be used? Amazon, Facebook, Twitter,
?
I think Facebook is the most evidently intrusive. They monitor all of your online activity pretty much and then shape your thoughts and such with targeted advertising. There will come a time in the future when the world decides it needs to take a step back from such intrusion in to their personal lives.
I am scared about Google. Facebook is something very optional, you don´t really need to use it at all. However, I find much more difficult not to use any Google service.