Twitter on Monday marked its fifth birthday with a new website and online video of celebrities talking up the world-changing micro-blogging service.

A video at the new website featured billionaire entrepreneur Sir Richard Branson, tennis star Serena Williams, astronaut Paolo Nespoli, rapper Snoop Dogg and others explaining why they use Twitter.

Jack Dorsey fired off the first tweets on March 21, 2006, an automated "just setting up my twttr" message which he followed with the first "human" tweet - "inviting coworkers."

It was Dorsey who proposed the idea for Twitter while working with Biz Stone and Evan Williams at podcasting company Odeo.

Since then, Twitter has been embraced as a forum for sharing anything from a favorite lunch spot to violations of civil rights and calls for revolution.

In a recent interview with AFP, Stone likened Twitter to a five-year-old child getting ready to go to kindergarten for the first time.

"It is just the beginning of a life full of potential and adventure, and I really do think that is where we are right now," Stone said.

"We are just about to go to school and just getting started," he said. "The last five years has really just been us getting our footing."