Virtually all the keyword tools sent out warnings of a major update that hit around August 21st. But the truth is, based on what I am following in the discussion forums, although there were some people talking about an update, it didn't seem like there was a major ranking shift.
Go ahead and check Mozcast on August 20th and then the other tools on August 21st, such as SERPs.com, SERP Metrics and Algoroo. They all show major spikes on the 21st, whereas Moz shows a major spike on the 20th.
Did rankings change? Was it a ranking algorithm change? Was it a penalty? Was it a user interface change? I am not sure. I suspect something major happened to the search results that made these tools spark up but the forums are not all that noisy.
Maybe the forum chatter is low because it is one of the last weeks of summer and people are away? But are webmasters ever truly away?
Did you notice any major change in your Google organic sourced traffic over the past few days?
I am honestly not sure what is going on or if it is worth me pinging Google about this.
Forum discussion at WebmasterWorld.
Update: Google has nothing to say about this topic.