So far in 2017 we’ve witnessed some fairly major algorithm changes, ranging from the mobile intrusive interstitials penalty to the now infamous Fred update.
The latter of those two for me is the most interesting. The Fred update was initially received by some members of the SEO community as a link based penalty, however data now suggests otherwise.
One thing that a lot of the losers of the Fred update have in common is the number of onpage advertisements shown. Websites that contain a large amount of affiliate links, or try to monetize visitors also saw a negative impact from the update.