Of course with the developer tools built into browsers these days, it only takes a few clicks to delete the nag layer and get to the underlying content. I wonder how they count me in their statistics?
It used to be easy to read the content off the html – no developer tools needed! Today, many websites are constructed to not serve the underlying content until the you've been served the ad.
By the way, I don't think there's anything wrong with what Springer is doing. Readers can pay cash, or pay by viewing ads. They can also choose not to read.