Mobile campaigns are a great way to connect with fans, offer exclusive content, and grow email lists. For the Cassandra Wilson mobile campaign, fans can opt in for mobile updates by texting "Cassandra" to 444999. After opting in, fans are given the option to receive a free song download by submitting their email to subscribe to the newsletter. Fans can opt out of mobile campaigns at any time by texting "STOP" to 444999, and can receive info by texting "HELP".