It's not often I can talk about Google SERPs in the Website Tracking and Analytics forum.... but whatever SEOs are seeing might not be what they think.
Over on Mozcast, the weather looks a stormy 80 degrees... which in lay terms means Moz thinks that there are huge changes going on in the SERPs. I think they are probably right, even though I have not looked at a single SERP in the last 48 hours. I do NOT, however, think that this is caused by a change in Google's algorithm.
Over the last 24 hours, Majestic started receiving more than average support tickets about sites whose Flow Metrics had suddenly dropped - usually to zero. I got so concerned that I even had to trouble the team team to check things... but absolute examples were a bit hard to come by. The issue seemed intermittent. We eventually put the problem not down to our systems, but down to one or more DNS failures on the web. When the DNS servers (wherever they were) recovered, so did our stats and at the next Fresh Index update (which was in the last hour as I wrote) the metrics I was checking seemed to recover. I assume any we missed will get sorted in the next 24 hours.
But... if Google's crawlers were also affected by the same DNS server outage, then they will also have found large numbers of websites offline. This will also have affected their graph and thus affected not only the sites offline, but others downstream that they link to.
So is today the Google Algo Update update that never was?