Early in 2009, a team of Google Web developers began work on the "next generation" of Google search infrastructure. The stated goal of the project, code-named Caffeine, was to help Google "push the envelope on size, indexing speed, accuracy, comprehensiveness and other dimensions" of Web search. The project was announced publicly in August 2009 in a post on Google's Webmaster Central Blog. In a separate blog post, Google software engineer Matt Cutts noted that, "this update is primarily under the hood: we’re rewriting the foundation of some of our infrastructure. But some of the search results do change."

In the meantime, we've conducted a number of test searches. The vast majority of the results seem to be the same in both searches however they are not in the same order. Additionally, the new Caffeine infrastructure seems to rank results from social networking sites such as Twitter, Linkedin, and Facebook higher than in the current search results.

Caffeine also seems to be living up to its size objective.  Test Caffeine searches for pages from an individual Web site (e.g. just from www.netforlawyers.com) returned 10% more pages than the same search from the current search infrastructure.

Google has made a preview version of the search available at http://www2.sandbox.google.com/.

Non-Google-affiliated Web developer Carter Cole has even created a page where you can search both versions of Google simultaneously and compare the results side by side.

Google has not yet announced when the changes incorporated into Caffeine will be "live" at www.google.com.