Triggered Campaigns, or simply Triggers, are a combination of a condition that needs to be met, and the action that should occur once that condition is met. In this case, the condition is met when an SMS containing a specified opt-out keyword is sent to a provisioned long code. The action is then to add the contact to the Tall Bob Opt-out List and send a confirmation message to the contact [if necessary]. This campaign could be a plain SMS, or it could contain a link to a landing page.

Setting up an Opt-out Trigger in Tall Bob