Twitter has taken the Cyber world like a storm. If you don't have a Twitter account you are as good as someone without email-ID in year 2000!
I have always wondered the reason behind Twitter phenomena and "until now" amazed about the stupendous popularity of this simple tool.
"Until now" - Why in quotes? What has changed now?
I believe the principle behind Twitter is age old, and much older generations have witnessed the principle behind Twitter.
IMHO the original Twitterati was Thiruvalluvar. He authored the Thirukural, from Wikipedia: "Thirukkural (or the Kural) is a collection of 1330 Tamil couplets organised into 133 chapters." Each couplets consists of 7 words and even the English translation can mostly fit into the 140 character limit of Twitter.
Other early Twitterati are: