Mobile marketing is growing rapidly, especially text messaging which has much higher open rates than email. Business SMS can benefit from the popularity of texting, with over 250 million Americans owning mobile phones. Experts predict text messaging will increase to over 10 trillion messages globally per year. Mobile marketing revenue is expected to increase dramatically from a few hundred million in 2008 to $3-5 billion in 2012 due to more time spent on mobile devices. Opt-in lists and transparency about messaging practices are important to build consumer trust.