So I assume from this response that we're talking about some sort of appended or purchased file? If so,
@Andy is right -- you're potentially in for some headaches.
"Triple verified" meaning what? That the email addresses themselves won't bounce? Does not matter. Have they signed up with you to receive email? If they have NOT, you can still use those addresses to specifically target those users through any number of ad networks (e.g., Google, Facebook, Twitter, etc.).
Within the U.S. (per CAN-SPAM), it is technically legal to send a SINGLE unsolicited offer to an email address. The email message must be clearly labeled as an 'ADVERTISEMENT', should include sender address, and must contain an easy, unobstructed opt-out mechanism. That initial offer must be a no-joke, high-value proposition, and should be an invitation to join, not a notification that they've been added to your list.
**BUT REMEMBER** if it looks like spam and talks like spam, it's spam. Users WILL complain. You should be prepared for the total obliteration of the sending reputation of the domains and/or IPs responsible for that message (and don't expect more than low-single-digit conversion rates -- at best).
Consider, though, a different scenario: A customer came to me and wanted to START an email newsletter. At first, he assumed we were starting from scratch as he "didn't have any" email addresses. As we discovered, though, he had a LOT of commenters on his website, and a published privacy policy that said we email commenters.
Starting from that list of commenters, we were able to 1) validate/verify addresses through a few scrubbing services to preemptively weed out invalids; 2) APPEND OPENERS using data vendors who can tell you who on a file is actually ACTIVELY opening emails (incl. a last open date). 3) We then started LOW and SLOOOOW, reaching out to users with an RSS-based email newsletter that sends automatically 3x weekly. Using the appended opener data, we started with very recent openers, and are SLOWLY introducing the rest of the file over time. As users OPEN and/or CLICK, they are shuttled into a new list that uses our 'better' delivery servers. (Ideally, engaged users are mailed from an entirely different ESP/IPs.)
THE MOST IMPORTANT THING is to be totally honest and open with your subscribers. In our case, we led with our face and (very prominently) said something like "THANK YOU for your continued support of Acme Publishing. You're receiving this email as a commenter on our website (as per our privacy policy). If you would prefer NOT to receive these emails, CLICK HERE to immediately unsubscribe." (Once the user CLICKS on CONTENT, change up their delivery servers. If they do NOT click after X messages, drop frequency. If they don't respond after X+Y, bite the bullet and purge them from your file -- but keep targeting them on Facebook, etc.)
If I can help, feel free to message me.
