Google is about to introduce a new index search technology called "Caffeine." This "new and improved" search engine is more than just and upgrade on Google: it's a totally different search engine that relies on a
completely new infrastructure (1). This new Google promises to be faster and more accurate than the old Google, to provide greater temporal relevancy (i.e., be focused on breaking news), and to provide a larger index size (i.e., display more results) (2).

The reason that Google has decided to launch Caffeine may be due to competition. Microsoft had recently brought out its new Bing search engine and had extended it to cover all of Yahoo's web features (3). The merging of Bing with Yahoo brought almost immediate payoff: the new Bing/Yahoo search engine had almost a 20% market share in searches last year, and that additional market share was coming at a cost to Google (4).

Even Facebook had joined the competition, joining forces with FriendFeed and launching a real-time search engine of its own.

More: http://www.associatedcontent.com/article/5493236/google_caffeine_attempts_to_beat_microsoft.html