In this CNET article by Declan McCulagh, he reports that the DoJ is planning to request mandatory data retention by Internet providers. Their argument is that the lack of data retention is interfering with law enforcement's ability to investigate cases. This implies some kind of shift in the balance of privacy vs. access. No such shift has taken place.
I think that they are more frustrated by the fact that a huge potential gold mine of information is out there to which they don't have access. Prior to the various modern technological revolutions people used pay phones, sent letters, and paid cash for toll roads.
Now they use Twitter, SMS, Facebook, Email, cell phones, electronic toll payment etc. There is way more information available to law enforcement now than before. The fact that this data retention is only on the Internet may make people feel better, but one would certainly learn more about me from my Internet activities than from following me around physically.
Lets look at what is being asked for with a real world analogy. This is like saying that the US Postal Service should photograph and database the address, and return address, on every letter which goes through the system. Physically is it like saying the cell phone company should record and retain my GPS location at all times. Either of those would actually be much less intrusive than monitoring how I use the Internet at all times.
Lets not get in to the cost of maintaining these records or the issues with leaks or hackers. Consider the Chinese attacks on dissident Google accounts. This plan would ensure that such information was much more widely maintained.
At this point it appears to be a only a request. I am curious to see how this evolves over the congressional term.