Mobile marketing is multi-channel online marketing technique focused at reaching a specific audience on their smart phone, tablets, or any other related devices through websites, E mail, SMS and MMS, social media or mobile applications. Mobile marketing can provide customers with time and location sensitive, personalized information that promotes goods, services and ideas. In a more theoretical manner, academic Andreas Kaplan defines mobile marketing as "any marketing activity conducted through a ubiquitous network to which consumers are constantly connected using a personal mobile device".
Once you've collected your mobile numbers, verified that you have followed all of your legal responsibilities you can start your SMS marketing campaign. I'd suggest using a 3rd party service provider to ensure that you are able to track the return on investment for your campaign, embed an unsubscribe message, and easily manage your SMS marketing database including unsubscribes.