Opt-in email marketing is one of the most reliable ways to grow revenue online. According to recent Omnisend studies, automated emails now drive 37% of all email-generated sales. Those automations only work on subscribers who said yes. The problem most ecommerce brands run into isn’t getting people on a list. It’s getting the right people… The post Opt-in email marketing: The complete guide [2026] appeared first on Omnisend Blog .