Google Ramping up with Caffeine; Here's how to Make the Most of Changes
On June 8, Google announced the completion of a new web indexing system called Caffeine, which provides 50 percent fresher results for web searches than the previous Google index.
Caffeine allows Google to provide more current, and therefore more relevant, content to the searcher much sooner after it is published than was possible before. Certain aspects of the Caffeine update have been visible for several months and Goodle officially announced that the updates have been completed.
See page 15 of the following link to read the full article.