Great insight, particularly the part about just opening mails to get the credits - that's something i'm definitely guilty of (a lot of the time i was already a member of the site being promoted using the traditional mailer approach). Listnerds has/is taking me down a different path looking for content I want to read and engage with and be inspired by, and it's great fun too. I still do read and open mails from those in the red zone to help complete daily, weekly and monthly tasks though - because it's easy to do so.