[DiapDealer]

Even if you manage to identify and strip out the bits that might identify the book as Amazon's, as B&N's, as Google's, or whoever's.... they (the retailers/devices) are still going to be collecting information about how long you read <whatever book it thinks you're reading>, if you finished it, how fast you read it, if the book has DRM, IP address, how many miles you are from the cell tower (if you have 3G), and numerous other things.

Calibre is (and should be) agnostic when it comes to things like this. If you don't want retailers to track personal things you're doing/reading on your ereader .... don't let your ereader communicate with the retailer. Calibre has no irons in this fire.