He received a statement from Google saying:
We expect to roll it out to all data centers over the coming months.
We run lots of tests with this big a change to our infrastructure. We want the new system to meet or exceed the abilities of our current system, and it can take time to ensure that everything looks good.
Again, many people will swear it is live. It is live, but only in one of the many Google data centers. So just be patient and hopefully it will go live before Bing powers Yahoo fully.
Forum discussion at DigitalPoint Forums.