I've watched one of those youtube make $100,000 of dollars from your own home videos once and they had a good sales pitch for using something like mail chimp. Basically you approach Etsy businesses to see if they have some sort of mailing system already set-up. If they don't you offer to use the emails from people who have already bought products and then send out promotions when the etsy owners approval like 20% off your next purchase for returning customers and then take some sort of % profit.

Off topic I know, but just goes to show how many creative ways people can make money.

Anyways 20somethingfinance.com is a blogger I follow and uses some sort of mail service. I honestly only visit his site when I get an email on something I'm interested in and would have quit visiting his site long ago if he didn't offer this sevice so from my perspective it actually works.