These Companies utilize Text (SMS) Marketing everyday to drive sales to their targeted (opt-in) customers. Their text messages then become Viral, meaning they can be forwarded on an unlimited basis to their friends and contacts via text forwarding. Promotions can be sent directly to the opt-in cell phone users and they can bring their cell phone (with message showing) to you to get the deals. You can also drive online sales via the internet by sending promotions to the cell phones and driving traffic to your website.
Text (SMS) Marketing is the only way to go if you want to drive immediate sales to your business on slow days, promotion days or any day you want to boost business. But you do need to be careful, if you send too many messages to your user base, they will opt-out and you will lose them forever, and they will tell their friends.