Vernon Robinson has tried to make a big deal about his donor list. There's no secret to it. He just buys the names here at Omega List Company as indicated in FEC reports and confirmed by "data cards"
Some of the same donors probably appear on similar conservative lists from Robertson Mailing List Company as the donors have given multiple contributions to other organizations that use this company.
The "data cards" give information about target audience, recent users, cost and terms. I think Vernon has a fondness for the GOPUSA email list because of the relative low cost of email, the other organizations that use it and support him and, because his printing/mailing expenses don't yet seem high enough to account for a print/mail campaign outside NC-13, unless of course he is piggy-backing on other mailings. Omega probably wouldn't be too pleased that his is giving away their product.