What Is Twitter ?

Introduction

Twitter is a service for friends, family, and co–workers to communicate and stay in touch, through small SMS type updates. The updates are an answer to a simple question, "What are you doing".Each message is 140 characters in length. It is also known as microblogging.
In order to use Twitter you should either have a computer or a mobile phone, along with an internet connection.

History

Twitter was crated in 2006 by Jack Dorsey,and is a privately funded startup with offices in the SoMA neighborhood of San Francisco, CA.  
Twitter has gained notability and popularity worldwide. Companies backing
Twitter are Union Square Ventures, Digital Garage, Spark Capital, and Bezos Expeditions (led by Jeff Bezos of Amazon).

How To Use Twitter

Crate an account on Twitter. Login and see the box " What are you doing". Write in the box and click on the Update button. Start sending messages, which are lovingly called tweets on Twitter.

References:
Photo Jack Dorsey from Creative Commons.Original Link to Photo By Joi.
Twitter About Page and  Wikipedia