And they'll sell your reading habit information. And since it'd be commercial the "pen register" jurisprudence applies meaning that the government can use it to

And they'll sell your reading habit information. And since it'd be commercial the "pen register" jurisprudence applies meaning that the government can use it to put you on a list. This last point is prevented for public libraries because being part of the government they're bound from gathering that kind of information under the first amendment.