Twitter celebrates 9 year anniversary

SAN FRANCISCO (KGO) -- Twitter is celebrating a birthday.

The San Francisco-based social media company was created nine years ago Saturday with the concept of allowing users to say whatever they want in 140 characters or less.

The service launched four months later and now has nearly 300 million users worldwide.

To mark the occasion, the company re-tweeted its first tweet ever, sent by co-founder Jack Dorsey which said, "Just setting up my Twitter."