I assume this is related to the "Enter your email to read this article" popup? As an aside, I used to work on a technical team that handled things like that on a relatively high-traffic website. I was told at the time that the rough "going rate" for an email address entered this way was $20.

This specifically always makes me wish that some kind of advertising revenue share would catch on and make this kind of thing feel like a win-win rather than feel as though I'm being exploited.