In the 18th century, philosopher Jeremy Bentham designed the Panopticon, meant for prisoners to be monitored by an all seeing guard, who himself, could not be seen. Comparing this to surveillance now, particular regarding the internet, even thought the metaphor is kind of bad. It is not too far off of what could be happening.
Anyone and everyone who is using the internet knows that their usage habits are being monitored; if you do not not know, now you know. It is called data mining. That is why when you are on Forever 21's website shopping for dresses, you see Forever 21 dress advertisements on Facebook not even minutes after you have clicked off of Forever 21. This technically fits in with how a company, whether Facebook or Forever 21, is watching your online activity similar to how a guard is watching several prisoners.
I am also going to take this time to compare internet users to prisoners within a Panopticon. Our data is constantly being mined and our usage being monitored, however, we cannot really do anything about it. Before using most of these websites, we usually make an agreement for said website to do so. This is similar to how prisoners cannot (and will not) do much about a guard watching their every move.
Now in relation to the government being said guard and internet users being "prisoners," the Panopticon metaphor is not the best. Although there are a vast amount of theories out, there is not an "all seeing government." At least not within the United States. It is completely possible for the government obtain information about a person if they absolutely have to, however, the government is not constantly watching millions of citizens.
To sum it all up, Panopticon metaphor for data mining? Good. For government surveillance? Bad.