It's the ninth birthday of the tweeting birdie. The very first tweet came from co-founder Jack Dorsey on March 21, 2006.
Since then, Twitter has now grown to more than 284 million users worldwide and expanding.
Dorsey, then an undergraduate student at the New York University, introduced the idea of an individual using an SMS service to communicate with a small group. The project code name for the service was twttr.
The project took off on March 21, 2006, when Dorsey sent the first Twitter message: "just setting up my twttr".
"We came across the word 'twitter', and it was just perfect. The definition was 'a short burst of inconsequential information', and 'chirps from birds'. And that's exactly what the product was," Dorsey has been quoted as saying in the context of the site's name.
Breaking news has also been a large part of Twitter's usage for some years now, with the 2008 news that the Mars Phoenix Lander had found ice on Mars being revealed by NASA via Twitter.
The US Airways flight that was forced to make an emergency landing on the Hudson river in New York in 2009 was also first reported on Twitter, with images of passengers on life rafts being re-tweeted.
The first suggestion for using a hashtag as a means of a creating a group conversation regarding a single event came in 2007 from a Twitter user Chris Messina.
The concept of trending has since become the informal yardstick of relevance on social media.
Most major events and even TV shows now come with their own hashtag, as organisers look to increase their online presence and get people talking and promoting their event.