YouTube will live stream TEDx Sydney 2011 all day this Saturday, 28 May, from 8:30am until 6:30pm AEST. Tune in to youtube.com/TEDxSydney to watch and take part in all the ideas, talks and performances. You can also find or host your own TEDxSydney satellite event and share the TEDx experience with others. Register your event here.

Here’s a sneak peek at the TEDxSydney line up:

The theme of TEDx is Ideas worth spreading. No better way to do this than by video. At YouTube, we’re big believers in the power of video to give people a voice. Since the first trip to the zoo uploaded almost six years ago, online video has become part of our daily lives, and altered the way we share cultural, artistic, and political phenomena. In that short time, we’ve seen daily conversations unfold and spread at incredible speed, aided by new technology and tools online.

We’ve seen videos around the world go viral (baby laughing at ripping paper, anyone?) and users jamming out and winning to the tune of 25 million views.

But powerful historical moments also come to life through online video. Earlier this year, the world looked to New Zealand on the day of the Christchurch earthquake, which became the second most viewed video of the day. Months later, events in Japan unfolded in real-time and the world responded. Only weeks ago, global audiences turned to their TV screens, their mobile phones, twitter and YouTube to hear the historic announcement from the White House.

In the spirit of ideas worth spreading, we’ve created a playlist of the 2011 videos, as found on youtube.com/trends, that changed the world, made you laugh, inspired you, and that you thought were worth spreading around the world. Relive, share, and upload your own.

Global Moments: Japan Earthquake, President Obama, The Royal Wedding, Riots in Egypt
Viral Hits: Rebecca Black, Songify This - Winning, Baby Laughing at Ripping Paper
YouTube Community Moments: YouTube Symphony Orchestra, You Talk to Endeavour
Local Moments: Queensland Floods, New Zealand Earthquake

Posted by Ernesto Soriano, YouTube Team, just watched Salman Khan TED 2011