How big is the signup abandonment problem for adult websites?

[anonymozo]

I would assume the abandonment rate on signup forms is significantly higher for adult websites than the average because of privacy concerns. Can anyone confirm or refute that? Also, is it true that a significant portion of emails entered in these forms are fake and useless for email marketing?

The signup forms on many freesites I looked at look like nobody cares if they are used at all. Is that the case?

Asking because I have a possible cure, but not sure if the problem is pressing enough for anyone to take the trouble of trying to fix it.