These new ad placements will be found at the bottom of the search engine results page (SERP) instead of ads that were previously shown to the right side of the results. The changes are being rolled out and will not always appear at the bottom of the page. Here is a screen shot of the new ad placement at the bottom of the SERP:
Google says that they dynamically optimize each search page, including its ads, to provide the best experience for their users. And in many cases, they have found that displaying ads below search results fits better into the user’s flow as the user scans the page from top to bottom, On average, placements at the bottom of the SERP performed better than side ads in terms of click-through rate (CTR) in their tests.
It will be interesting to see how these new ad placements will affect CTR and conversion performance. In order to gauge performance, you can run a “Top vs. Side” report to see where your ads perform best. All side, bottom and experiment impressions will now be classified as “Other” so you can see how your top placements performance against the other placements on the page. Google says that the report name will be renamed to “Top vs. Other.”