Robert_Charlton - 11:21 pm on Jan 5, 2008 (gmt 0)

Here's another observation. I recently found several examples of a fall from #1 to #7, instead of #6. In each of those cases the top five positions included an indented (clustered) result.

I've seen this too, on one example page, with that page staying in the #7 spot for about three weeks.

Several days ago, though, I began to see some movement in the top results. For a short time, the clustering above disappeared and, simultaneously, a competing page dropped below the example page, which then moved into the #5 spot.

Now the clustering is back, and the example page is at #6, with the newly dropped competitor now in the #7 spot.

Hard to generalize from this one example, but it might be that they're rotating results out of the top five, perhaps based on whatever perceived weakness... perhaps just a test... and then trying the same with other pages.