There has been this steady chatter for the past few days around webmasters and SEOs seeing ranking changes and fluctuations in the search results. It's been ever since what I thought were false reports of a Google update earlier this week.
The chatter has not died down but it is still what I would consider to be light chatter.
It might be Google is testing Penguin or some other ranking algorithm change in the search results on a subset of users. And when they are testing it, some users are seeing it and when they come back, the test might not be running. So their rankings jump up or drop down and then it goes back to where it was, like you'd see with any test.
The various tools are seeing it also, at least some.
Mozcast has been pretty warm the past few days:
SERP Metrics has been jumping all over the place the past few days:
It is hard to say but I see comments like this at WebmasterWorld:
Since yesterday I'm seeing 2 datasets switching by the minute.
I've seen important changes in the past 2 days in positions 80+ to 180-/+ on a particular search phrase that involves location and business type. So far, I'm happy with the shuffle happy!.
What do you think?
Forum discussion at WebmasterWorld.