CainIV - 6:06 am on Jun 22, 2011 (gmt 0)
I think this makes to look at in terms of aggregate factors that those interviewed believe are in play across a large number of genres.
Don't forget that the factors are likely a measurement across similar players in the same vertical.
For example, if you are not currently using diverse inbound marketing tactics, and nor are any competitors in your vertical (or their signal is not strong) then you may not notice any difference, and in fact could continue to rank well, even without (for example) social media.
So I believe these metrics are measured from competitors on a vertical and likely a query intention baseline.