Another tidbit that came out of Google Paul Haahr's SMX West talk was an experiment Google ran before he even joined the company 14 years ago. He said they ran this long term experiment from 2001 or so through 2005 where they would swap positions 2 and 4 to 0.02% of the searchers.
He said he wasn't sure on the percentage, but it was a small subset of searchers. They ran the test for years and years.
The thing is, many SEOs back then would have sweared noticing this. I know we covered people talking about it back in 2004, but I cannot find the blog posts now. In any event, it is funny that he said it and then Danny Sullivan was like "I knew it!" as a joke.
He said it would show that position one would get way more clicks when they swapped position 2 with 4.
Here are some tweets:
for a long time back in 2005 and earlier, Google had an experiment that swapped 2 & 4 positions. to ~0.2%. more people clicked on 1 #smx— Barry Schwartz (@rustybrick) March 3, 2016
Reminds me of my post from 2013 Google's Cutts Say Search Flux Not Meant To Trick SEOs?
Forum discussion at Twitter.