From an SEO perspective there's nothing new here, although it may well be the most transparent Google has ever been about utilising CTR (click through rate) data in their natural search algorithm. This is something that we at Greenlight have suspected since Google was granted the rank adjusted content items patent that suggested click patterns could be used in various ways to inform rankings.
This serves as a reminder, if one were needed, of the importance of the following (in this order, I'd suggest):
- Using microformatting to create "rich snippets" that enhance your search engine result page (SERP) listing with additional information such as product listings, comments, post counts, ratings and reviews
- Optimising your title and meta description so that they are compelling and readable, not just keyword rich
- Having a clean, concise URL structure so that users can see from the display URL that the page they are going to is the right one
Related to this, we conducted some research around Google ranking fluctuations a little while back. It's accepted wisdom in search engine optimisation (SEO) that rankings will fluctuate, sometimes by a little, and sometimes by a lot. At Greenlight we already rank check an eye popping number of keywords on a pretty regular basis, but for this test we decided to up the ante. We took 1,000 keywords and recorded the top 100 ranking sites for those keywords 10-15 times over the course of a single 24 hour period. This resulted in a record of approximately 1,000,000 URLs, and the ranking fluctuations they had experienced within the space of a single day (starting and finishing the test in the evening).
Of the recorded ranking URLs, 82,480 experienced at least one fluctuation of at least one ranking position - 8 per cent of our data set. We observed what appear to be three distinct patterns of ranking fluctuations in our test. These are: day / night fluctuations, permanent or semi-permanent rank changes (what we'll call "normal" fluctuations), and algorithm / user testing.
There's an interesting link between the cyclical rank fluctuations we saw in our experiment (what we termed "Algorithm Testing or User Testing Fluctuations") and Google using CTRs in its algorithm. We concluded that the alternative scenario here is that Google is testing how well users respond to a particular page ranking in the search results by artificially improving its ranking for intermittent periods, looking at user signals like CTRs, bounce rates, engagement time and so on.
Google's transparency over using CTR adds a lot of credibility to this theory (not that knowing this is much use to anyone, since by the time you identify cyclical rank fluctuations Google has probably already tested your CTR performance).
*(The author has trained, strategised and provided consultancy for clients including Vodafone UK, American Express, Monarch, Legal & General, Santander and Sky)