I have heard of national ID cards, implants that track our movements, and having a database that tracks everything we do. And some of those things are going forward (the implants are supposed to be ready by 2010 or so).
There is only one justifiable use for this tracking. In case of strongly suspected terror activity, it might help stop the terrorists. However, the potential is that they will cry terror just to make an "emergency" out of something that is not critical, just to impose controls that are not necessary. They might also make criminals out of people that just want to watch porn, smoke a little weed in their own homes, or browse web sites that might contain critical material. None of which is a genuine threat to society, and therefore should be none of the government's business.