Looks like Google planned to be the biggest news of the day, and they won the news cycle - taking it from Microsoft, who expected to have buzz around Bing. Via TechCrunch:
So what happened? Well, the company that will do no evil will certainly engage in a little stealth black ops mission when its required. Google knew full well exactly when Bing was going to launch. And they carefully planned the Wave launch to occur just minutes afterwards. They knew the crowd was ready for something cool. Not only did they have that free phone, but the day before Google VP Engineering Vic Gundotra told the crowd that there would be a big announcement the next day. People were ready and willing to be wowed.
They timed that right as MS was finishing the announcement of their renamed search engine (Bing) - and before the website went live. Looks to me like MS should have made sure the site was live before they went public. It's too bad, too, because if this video shows the tool the way it works, it could be pretty cool.