Social Networks cooperation with U.S Govt

I just finished watching the documentary “Terms and Conditions May Apply” which outlines how social networks, tech companies, etc collect massive amounts of data on it’s online users and allow govt agencies to access this information.

Now I can see how this would be extremely valuable for companies who want to advertise more efficiently, tailor products/services based on the information they have on their consumers. But the real question is, whether or not govt would be disciplined enough to only use this data for the prevention of “terrorist” attacks or would it be used to prevent any kind of opposition or resistance to their policies. Would any opposition to govt actions or policies eventually be considered as “terrorist” attacks?

I’m under the belief that a collection of data so valuable in the control of such a powerful entity will inevitably be used for their benefit, whether or not it negatively affects the public. With that being said, be careful what you post on social media people. If you plan on taking actions that may not be liked by higher powers, do what La Cosa Nostra does and always talk in person somewhere under a bridge.