Unnamed Major Update — November 10, 2016
MozCast detected a major (106°) spike on November 10th and another on the 18th. Industry chatter was high during both periods, with some suggesting that the second spike was a reversal of the first update. Google has not confirmed either event. Many people reported bad dates in SERPs during the same time period, but it's unclear whether this was causal or just a coincidence.
Penguin 4.0, Phase 2 — October 6, 2016
The second phase of Penguin 4.0 was the reversal of all previous Penguin penalties. This seemed to happen after the new code rolled out, and may have taken as long as two weeks. Post-Penguin activity had one final peak on October 6th (116°), but it is unclear whether this was Penguin or a new update. Algorithm temperatures finally started to drop after October 6th.
Penguin 4.0, Phase 1 — September 27, 2016
The first phase of Penguin 4.0, which probably launched around September 22-23, was the rollout of the new, "gentler" Penguin algorithm, which devalues bad links instead of penalizing sites. The exact timeline is unconfirmed, but we believe this rollout took at least a few days to fully update, and may have corresponded to an algorithm temperature spike (113°) on September 27th.
Penguin 4.0 Announcement — September 23, 2016
After almost two years of waiting, Google finally announced a major Penguin update. They suggested the new Penguin is now real-time and baked into the "core" algorithm. Initial impact assessments were small, but it was later revealed that the Penguin 4.0 rollout was unusually long and multi-phase (see September 27th and October 6th).
Image/Universal Drop — September 13, 2016
MozCast recorded a nearly-record 111° temperature and a 50% drop in SERPs with image (universal/vertical) results. The universal result shake-up opened up an organic position on page 1, causing substantial ranking shifts, but it's likely that this was part of a much larger update.
"Possum" — September 1, 2016
While unconfirmed by Google, MozCast recorded extreme temperatures of 108° and a drop in local pack prevalence, and the local SEO community noted a major shake-up in pack results. Data suggests this update (or a simultaneous update) also heavily impacted organic results.
Mobile-friendly 2 — May 12, 2016
Just more than a year after the original "mobile friendly" update, Google rolled out another ranking signal boost to benefit mobile-friendly sites on mobile search. Since the majority of sites we track are already mobile-friendly, it's likely the impact of the latest update was small.
Unnamed Major Update — May 10, 2016
MozCast and other Google weather trackers showed a historically rare week-long pattern of algorithm activity, including a 97-degree spike. Google would not confirm this update, and no explanation is currently available.
AdWords Shake-up — February 23, 2016
Google made major changes to AdWords, removing right-column ads entirely and rolling out 4-ad top blocks on many commercial searches. While this was a paid search update, it had significant implications for CTR for both paid and organic results, especially on competitive keywords.
Unnamed Update — January 8, 2016
Multiple tracking tools (including MozCast) reported historically-large rankings movement, which Google later confirmed as a "core algo update". Google officially said that this was not a Penguin update, but details remain sketchy.