How many SMS messages are sent every day?

Most people used their mobile phones to send SMS messages because it's more convenient for us to commucicate without seeing each others.
Here's some information about how many SMS messages are sent every day.

Short Message Service (SMS), or text messaging, has proved extremelypopular among GSM users, with an estimated 1 billion SMS messagesbeing sent every day globally1. With SMS the user can send short textmessages directly from one mobile phone to another.

http://answers.google.com/answers/threadview?id=316685 (Google Answer)