Cult of Mac's Leander Kahney says that the reason behind today's Apple event streaming is to test their new server farm in Maiden, North Carolina. According to his source, "the goal is to monitor traffic load and quality."
Apple's new $1 billion data center is one of the largest in the world. Today's web broadcast will require a titanic processing and data transfer effort to serve hundreds of thousands of simultaneous connections at different video qualities. The streaming uses HTTP Live Streaming, a proposed web standard that hasn't been adopted by anyone except Apple. This is why it will be only available for Mac OS X and iOS devices. [Cult of Mac]