If you now visit Google Caffeine page http://www2.sandbox.google.com/, you will the message

Thank You

You will also see the message

We appreciate all the feedback from people who searched on our Caffeine sandbox.

Based on the success we’ve seen, we believe Caffeine is ready for a larger audience. Soon we will activate Caffeine more widely, beginning with one data center. This sandbox is no longer necessary and has been retired, but we appreciate the testing and positive input that webmasters and publishers have given.

Its not surprising. Google Caffeine will soon be launched for the masses.