Google Instant - the search enhancement introduced in the fall of 2010 that shows results as you type – was based on Google’s insight that people type slowly, but read quickly, typically taking about a tenth of the time to glance at another part of the page. With Google Instant you get to the right content much faster because you don’t have to finish typing your full search term, or even click “Search” before getting results.
Benefits (as listed by Google) and Search Marketing Impact
Benefit: Faster Searches
Impact: Competition for shorter keyphrases
By predicting your search and showing results before you finish typing, there will be greater competition for shorter keyphrases. For example, as someone starts typing in your niche term ‘Chocolate marshmallow squares’ they see results for ‘chocolate’ and ‘chocolate marshmallow’ as they type in the search field and may decide to stop and take a look at results being presented along the way.
Benefit: Smarter Predictions
Impact: Keyword selection
The top prediction is shown in grey text directly in the search box, so you can stop typing as soon as you see what you need. This can actually help marketers with keyword research in that the terms that appear at the top of the list are likely the most common searches and ones you should consider using.
Benefit: Instant Results
Impact: Impression counts rise
Start typing and results appear immediately whereas until Google Instant, you had to type a full search term, select Search, and hope for the right results. Google counts any pause of three seconds or more as an impression, and so your Adwords account may see a rise in that area.