When someone from your audience opts in to one of your mobile messaging lists, it's like you are beginning a new relationship with them. Because of that, Welcome Messages and Welcome Series are imperative to starting that relationship off on the right foot. As you begin to curate your Mobile Welcome Series, you'll want to keep these three key steps in mind:

Follow Opt-In Best Practices: Get an explicit opt-in and follow protocol
Make a Good First Impression: Begin your relationship with a Welcome Message
Map Out the Series: Craft a series of messages specific to your subscriber