Yes, private companies have records of any and all of your activity involving the use of their services: telephone companies have information on all calls to and from their subscribers, ISPs have information concerning the sites accessed via their service, email providers store copies of your email correspondence on their servers, credit card companies and banks store information regarding your non-cash purchases, etc. But no one of those private companies is collecting and storing (nor are they permitted to collect and store) information across such a wide array of services by multiple providers, then analyzing and cross-referencing that data from multiple providers in such a way as to provide a comprehensive picture of a person's activities (and then drawing conclusions about what that person is up to based on those activities). And there are laws governing what data those private companies may collect and store, and to whom, and under what circumstances, that data may be released. So to frame this issue as merely a question of who collects data, private companies or the government, fails on the face of it. Private companies will continue, as they always have, to collect information related to the use of their products or services. The question here is whether government can be trusted to collect from across all these companies for purposes of analyzing it and cross-referencing it, regardless of how the government claims it is using it.
Now, some may say that all of this is perfectly fine and acceptable in pursuit of the goal of thwarting potential terrorist attacks. But here's the thing: neither those folks, nor anybody else save those who are privy to the details of these programs, can really know whether that data is being used only for the purpose of thwarting potential terrorist attacks. It is critically important to take a long view on these issues. Even if you have absolute trust in this President and his administration that they will not in any way misuse this information, what assurance do you have that the next one, or the one after that, will not do so? With the administration fighting so furiously to keep the details of the program secret, and to keep it relatively free from judicial oversight, where are the checks to prevent some future President from directing the NSA to cross-reference all that data in such a way as to identify persons who may be involved with, say, a political organization to which that President is opposed?
Your post also seems to take an all-or-nothing view of privacy in the way you suggest that because people voluntarily (or not so voluntarily, in some cases) disclose certain information, that we shouldn't even bother trying to put into place any protection for the privacy of ALL information about our selves. If that's where you are going with this, then we might as well use the Fourth Amendment as toilet paper, because that's about all it will be good for.
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