Before Google Instant you would just do a search in Google, press search and back came results…. so what could possibly have changed?
Well although not entirely new Google Instant allows you to see the results as you type your search query. This saves you time and also helps you narrow the search faster. Google reckons this will save you as much as 2-5 seconds per search.
So should you be concerned? … eeerrr yes.
If you are trying to get to the top of the search engines with broad terms then you are likely to miss out as the user refines their search. They want the best result to match their search requirements and will be refining them quickly missing more broad terms as they go.