How do sms sending sites work?

How do sms sending sites work?

There are sites like www.way2sms.com or www.160by2.com which send text messages to mobiles (in India). What I wonder is that, the recipient gets the message from my own mobile number instead of some arbitrary fixed mobile number (like how facebook sends its text messages to mobile). I wonder how such a system would work. How can they send a message from my mobile number. I could think of infinite possibilities using such a system.

ANSWER

To send SMS through internet you need a SMSC (Short Message Service Center) connectivity. In India mobile operators do not provide this connectivity directly (but can be get through an aggregator) to the end users but in other countries you can get it through your mobile operator.

This SMSC connectivity requires connection through an interface, which includes Web Interface, REST API (http url), XML API and SMPP. Some operators also provide advance connectivity options but as a normal customer with moderate use a REST based API is best bet.

Once you have the connectivity with an operator or aggregator you can use any programming language like PHP, ASP.NET, JAVA etc to build your application.

Disclaimer: I am the founder of znisms.com (ZNI Wireless Pvt Ltd) a SMS aggregator in India.