I don't know if you guys have noticed but buying and mailing 3rd party GI data is getting more and more expensive daily from spam traps, complainers wilin out, legal risk from certain offers, pissing off hosts, ruining ips, and haus. And from what I've heard it is getting more difficult to find IP space to deliver to TLDs, I could be off base here. Can we start a discussion on building permission based lists and generating our own data? Are there any good resources or books on it? Everyone is selling data and cleaning services and no one is talking about how to build a double optin list. Is that outside the scope of the forum?