I landed 2 more clients for my newsletter-as-a-service business: www.emailatscale.com and redesigned the landing page to speak a bit more to the benefits that my clients get and the pain points that my service solves.
So far I've had the best success with SaaS founders who have large mailing lists but don't have content to send to that list every week. Using curated content has allowed them to send valuable articles every week and promote their webinar or free trail alongside it.