"When Barry asked me about "position 6" in late December, I said that I didn't know of anything that would cause that. But about a week or so after that, my attention was brought to something that could exhibit that behavior. We're in the process of changing the behavior; I think the change is live at some datacenters already and will be live at most data centers in the next few weeks.In general if you think a site might have a penalty (perhaps from past behavior) and you think the site is clean presently, you can do a reconsideration request in our webmaster console to ask Google to take another look at the site."
From an industry point of view, it's great to know that Google and specifically Matt Cutts are active in forum discussion and take note when users notice something strange. If your site was affected by the penalty, let us know!
Posted by Matthew Elshaw at 7:45 AM GMT