There are few people that would welcome someone spying on them 24/7, monitoring all their conversations, all their movements, and all their activities, as doing so would not only be a broad breach of someone's right to privacy, but also the activity of a de facto police state apparatus in action. Yet today, it has never been easier to track someone and their proclivities, even in their own home, which certainly appears to be a direct violation of our 4th Amendment rights to be protected against "…unreasonable searches…" Yet, in a nutshell, when we connect to the internet through our Internet Service Provider, we are, through our IP address which uniquely identifies our account with the ISP, are being tracked as to the websites that we visit and this information is kept on the ISP server logs, long after you have forgotten what websites that you visited on a given day.
There isn't any doubt that if you know the web addresses a given person visits day after day, that this information in conjunction with other "public" data about you will allow the recipient of those details to be able to construct a very accurate representation of your characteristics and your habits, and thereby to know you in a way that in the wrong hands could easily compromise or embarrass you. Of course, your ISP will be quick to point out to you that as a condition of you using their service, you have agreed to certain Terms and Conditions, but those Terms and Conditions do not mean, that they are right, that they are legal under all circumstances, and further that the divulging of this information to government or other agencies, is some sort of nebulous benefit to our country that somehow trumps your individual constitutional rights.
Media companies have become quite annoyed at the reduction of their revenue through the illegal downloading of their copyright materials, and have taken steps to track back IP addresses that have been seen to infringe upon their property through peer-to-peer network sharing, so that they have taken upon themselves to provide this infringement information to the ISP provider, whereupon that ISP provider then sends an email "alleging a copyright violation", to the IP address on file. This given policy seems fundamentally flawed, that is to say, if the media company knows for a certainty that a particular peer-to-peer networking connection contains their copyrighted material, they then should either seek an injunction against this activity or interdict the connection or something of a similar nature. Instead, after the fact, they accuse the IP address holder of having copyrighted material solely based on alleged internet activity without actual verification that this is indeed true.
The bottom line, in fit and function, is that your ISP is either directly monitoring your internet activity, and/or implicitly has the power to do so, and/or implicitly gives itself the power to forward such information to government or other authorities, all as a "condition" of you, utilizing the ISP. It would be one thing, if the ISP provided you internet connectivity free of charge, and as a condition of doing so, you voluntarily gave up your privacy rights, something akin to the usage of Facebook, but in point of fact, you are paying them good money for a service, and they are in essence, spying upon you, and, in some cases, placing you in a position, that your monitored activities will theoretically incriminate you.