SMS Gateway is your link between the World Wide Web and the world of cellular phones through which short text messages are sent. Basically it is a website that permits you to send SMS messages from a web browser to people who are within the limits of the cell that is serviced by the gateway. It permits the communication of SMS messages to and from mobiles from another media source. To put it simply, sending short e-mail messages to manifold mobile phone owners is the best example of a SMS Gateway.
These days thanks to the internet, even the bigger companies are trying to reach as many people as they can to canvas their products. This they do by sending bulk text alerts to a plethora of mobile phones. They avail of a database service for this purpose thereby targeting thousands of customers in one shot.