Advertisers use SMS Messaging and Voicemail to extend their campaign to the phone by including an option in the ad that lets viewers send an automated SMS message or voicemail message. With SMS messaging, advertisers give users the option to enter a mobile phone number for themselves or a friend to get text reminders about a show, movie, product or service. With voicemail, advertisers give users the option to enter a phone number to get a greeting from a celebrity or other compelling audio content. Take a look at ads that have used this feature.