Interesting business model.

Sell verification services to one set of clients, and use the harvested email addresses to sell spam delivery to another set of clients.

It's like having a space in a big building downtown with storefronts on two opposite streets. Babysitting/childcare services here; rent a child to go the park with and help you pick up chicks there.

The similar playing-both-sides against the middle that I'm struggling with right now: companies sell (physical) mail addresses to other companies for beaucoup bucks. But if you want to correctly report that your wife has been dead for 9 years because you're tired of getting her USPS spam, they want to charge you to add you to their profitable database.