Google Instant Search is a kind of revolution in the range of search engine results pages. The new function available in the US at first and globally inside Google accounts is showing suggestions below the search engine form and relevant dynamic search engine results while typing. The suggestions become more precise with the number of letters entered and do end with more detailed suggestions, when the complete search query is submitted. The same happens to the dynamicly displayed search engine results. These suggestions and available views are aimed to ease the navigation and searching by the fact that people do view faster than they type.
Up to now it is unclear how this will impact search engine marketing and optimization. At the beginning of the typing process irrelevant results do appear statistically followed by more precise results, which may enrich the overall experience. By this one may speculate that more results of the long tail will be accessed. Another interesting and important speculation has been brought up by a SearchEngineWatch article thinking about the consideration of trends within the search results. So there might be more up to date results, which is in the trend towards the realtime web.
Below are links to the official introduction of Google Instant Search, the official Google blog post about the launch including a video and the mentioned article by SearchEngineWatch:
Google Instant (official site including information for advertisers)
Search: now faster than the speed of type (official Google Blog about the launch)
More on Instant Search (Google Analytics Blog)
Google Instant – 10 Things Marketing Teams Need to Know (SearchEngineWatch Blog)