I have one book in particular that is quite widely pirated (which I know from Google Alerts). It was published in 2002 and OOP since shortly thereafter, but I get easily 1-2 emails a month about that book. That’s a long time to have persistent emails and that interest can’t all be coming from print readers — the print run was just too small. I’m pretty sure a lot of those readers are going on to check out my in print titles and I do know that some of them are getting the print copy of those. In this case in particular, I think it would be unwise to take down those shares — under the current conditions.

And as you say, that person is likely a college student and judgment proof anyway. (Although I note that if you win a copyright infringement suit you get attorney’s fees.)

That’s not to say I think the law is wrong in defining who the infringing party is. It’s just that the reality of who is liable in these cases makes it nearly impossible to prevent or even discourage copyright infringement on the Internet, which is also why (like you) I rarely bother with sending takedown notices.