It seems Google may have tested a search algorithm update yesterday late morning and then may have pulled it back.
The ongoing WebmasterWorld thread has chatter from the SEO community around the update but the chatter soon died down after things settled back. Plus most of the automated Google SERP tracking tools show very little fluctuations, if any.
Here are some of the posts late yesterday morning at WebmasterWorld:
comparative to yesterday my traffic is up with about +25%
Something major appears to have rolled out just after yesterday's short, hour long surge of excellent converting traffic. Today it's back to 1 or zero on the site.
I'm seeing plenty of ranking changes for my site. I regained dozens of previously dropped key phrases. A few downward moves, but only -1 or -2, but at the same time many +3 and +4 deltas. BUT......
Woke up to almost double traffic, im almost at my daily visits of 3k unique s already and its 10 am here in the uk, something is happening here, anyone else?
Clearly, timing based on these posts in the forum is hard to nail down. The webmasters can be looking at different metrics that are delayed or not real-time.
Both SERPs.com, SERP Metrics and Advanced Web Ranking tools to show a slight uptick in changes in the Google search results.
Maybe something big is coming and this is just an early sign? We are due a Panda update. :)
Forum discussion at WebmasterWorld.