In my previous post on 'Google Instant Search Now Live' I have explained about the Google Instant and how it benefits the users. Although Google Instant doesn't change the way ads are served, ads and search results will now be shown based on the "predicted search." With this change, you might notice some fluctuations in AdWords impression volume and in the distribution of organic keywords. You may find that certain keywords receive significantly more or fewer impressions moving forward.
As a user starts to type a search, Google Instant automatically shows results for a popular search that begins with those letters. An algorithm tries to predict what the rest of the query might be based on popular queries typed by other users. The predicted text is shown in light grey in the search box, and search results and ads are automatically shown for that predicted query.
For example, if someone types "flow" into Google.com, our algorithms predict that the user is searching for "flowers" (the predicted search) and therefore display both search results and ads for "flowers". However, if that user then adds the letter "c" to the query, our algorithms may predict that the user is searching for "flowchart" and show the corresponding natural and paid results for flowchart.
The user begins to type a query on Google and clicks anywhere on the page (a search result, an ad, a spell correction, a related search). With Google Instant, an impression is counted if a user takes an action to choose a query (for example, presses the Enter key or clicks the Search button), clicks a link on the results page, or stops typing for three or more seconds.
Google Instant might increase or decrease your overall impression levels. However, Google Instant can improve the quality of your clicks since it helps people search using terms that more directly connect them with the answers they need. Therefore, your overall campaign performance could improve.