tedster - 6:48 pm on Nov 12, 2006 (gmt 0) So I'm not sure we've got a complete understanding right now.
Are many people seeing this "new kind of supplemental"? I've just gone through several ecommerce sites that I work with and I see no sign of it. One of them is under 1000 urls total, so I can see every one easily -- and NONE have a Supplemental tag. I know for sure that each product on this domain does not have an IBL. Not anywhere near that. And most of them are 3-clicks from the domain root.
So I'm not sure we've got a complete understanding right now.