According to a recent study from the Pay Per Click Marketing Blog, the author found that 60 percent of user clicks come from the link in the first position on Google's search engine results page (SERP). If you're in second position, you receive around 20 percent of clicks, while 3rd position sees just 10 percent.
This isn't groundbreaking news to SEO marketers. However, the blog also found that the remaining 10 percent of clicks came from ads on the right-hand column.
Google recently announced on its AdWords blog that it's now tinkering with that remaining 10 percent, as ads shown on the sides of SERPs may be shown below them instead. Why, you ask? Because Google found that clickthrough rates were higher when integrated into the bottom of SERPs instead of displayed on the side.
Company officials added that bottom-placed ads fit better into a user's "flow" as they scan a page from top to bottom. This means that if you're using analytics software to track how side column-based ads are performing, you may have to revamp your analysis process to account for the new placement.
It's important to note that when ads appear on the right of SERPs, no ads will appear on the bottom, and vice-versa.