A reply to a text message is one of the clearest signals a business gets that someone is genuinely interested, and that moment is exactly where Facebook Custom Audiences becomes useful. Mobile Message can pass that inbound SMS straight through Zapier, and Facebook Custom Audiences can turn it into an update to the ad audiences a business is already running.

Once that connection exists, a customer replying to a text can add their email to a custom audience, putting them in front of retargeting ads while the conversation with the business is still fresh in their mind. A second automation covers messages that don't land. When a text fails to deliver, that contact can be removed from the custom audience instead, keeping wasted ad spend away from people a business can't actually reach by phone.

None of this requires digging into Facebook's ad tools by hand every time a reply comes in or a message bounces. The audience stays current with how customers are actually responding, so the ads a business runs stay pointed at people who are engaged rather than people who never got the message in the first place.