Mobile marketing is growing rapidly, projected to increase from $2.7 billion in 2007 to $19.1 billion in 2012. It differs from internet marketing in that mobile devices are personal, ubiquitous, allow for immediate responses, provide location data, and are used by most people daily. Effective mobile marketing uses SMS, MMS, apps, widgets, Bluetooth, location data, and other methods to reach customers with content, games, information and ads. Case studies demonstrate using SMS voting at events, mobile websites and emails to promote campaigns, and Bluetooth file sharing. Issues include cost, potential intrusiveness, and platform fragmentation, but mobile is an important part of marketing mixes as people increasingly use mobile internet access.