This site did not show evidence of storing passwords in plaintext.
This site does allow secured connections (https)
This site did show a clear way to unsubscribe from their emails
This site does verify your email address.
Below is a sample of the emails you can expect to receive when signed up to Firstgrabber.
Welcome to FirstGrabber Affiliate Program, please use the link below to confirm your email, after that, please allow us 2 ~3 business days to review your application request and notify you whether you are approved or not.