A lot of people are saying Caffeine has been wildely deployed after the Caffeine Sandbox has been retired. But Matt Cutts has clarified that “Google is ready to go live with Caffeine at one data center. This means that a small percentage of Google’s users will benefit from the technology behind Caffeine in their regular searches.”
But he did assure that full Caffeine roll out will happen after the holidays. “I know that webmasters can get anxious around this time of year, so I wanted to reassure site owners that the full Caffeine roll out will happen after the holidays. Caffeine will go live at one data center so that we can continue to collect data and improve the technology, but I don’t expect Caffeine to go live at additional data centers until after the holidays are over.”
Source: Matt Cutts
