Shaquille O'Neal announces retirement on Twitter

Instead of holding a press conference, Shaquille O'Neal announced to his nearly 4 million followers on Twitter that he is retiring from the NBA after 19 seasons.

In a video (using Tout, a real-time video messaging service) posted on his Twitter account, Shaq, 39, says, "We did it. 19 years baby. I want to thank you very much. That's what I'm telling you first. I'm about to retire. Love you. Talk to you soon." To watch the video, click here.

Shaq is the NBA's fifth all-time leading scorer (28,596 career points) and has four championship rings (three with the Los Angeles Lakers and one with the Miami Heat). He was the first overall pick in the 1992 draft (selected by the Orlando Magic) and also played for the Phoenix Suns, Cleveland Cavaliers and Boston Celtics.

"I tried to make people happy and I tried to have fun. I think I did both," Shaq says. He will be holding a press conference on Friday at his Isleworth home, where he will talk about his prolific career.