What will not change
Here's the thing - This is not a bad change but it slowly alter the way that visitors search Google's database. Instant will not immediately change your rankings - nor
Certainly, the definition of an impression will evolve as Google pushes more and more sponsored ads out into the search-o-sphere. However, I don't see this increase of information is going to be easy on the eyes of my 70-year-old parents. I seriously doubt they will be clicking more ads than they currently may in a given day.
What will change?
User behavior will change over some unknown period of time. That evolution will have an effect on your organic and paid search optimization.
How? Well, the keywords that you use now are either based upon your past experience or based upon search traffic trends from search engines over past months.
As Google suggests more keywords with search results then it goes to follow that visitors will unconsciously use those suggestions on their way to a solution. We have always followed trends of traffic based up on what visitors USED to type on their own. Now Google is guiding their pattern with some auto-magic Google logic...
One has to assume that Google has their best interest at heart and that means the change is profitable for them. They are already
Example: The moment I type in "tra" on my way to trap, travel, transcript, etc... The first suggestion is "Travelocity". Not only is Travelocity not the top keyword by volume for this prefix, but it's also a TRADEMARK.
I type in "be" and I get "Best Buy".
"Ta" gives you "Target"...
It doesn't take a whole lot of experience in the SEO realm to know that they have a cash cow hanging in the shed.