As you might have noticed, Google has rolled out a major update and removed all ads located on the right side of its desktop search results.

From now on no more ads will not appear on the right side of desktop search results, except for product listing ads (PLA), which show either above or to the right of search results
as well as ads in the knowledge box.

As well, Google now may start showing an additional 4th ad above the natural search results for what Google calls “highly commercial queries.”

Google’s official statement about this subject:

We’ve been testing this layout for a long time, so some people might see it on a very small number of commercial queries. We’ll continue to make tweaks, but this is designed for highly commercial queries where the layout is able to provide more relevant results for people searching and better performance for advertisers.