tedster - 4:23 pm on Dec 10, 2011 (gmt 0)
Ah, I understand. However, other areas of the total algorithm also have been showing signs of machine learning. and that's been for several years before the Panda component was added.
For example, our members here have long been watching "waves" of ranking changes, particularly in the deeper pages of the SERPs. Google apparently prefers this machine-learning method of tuning the over all algorithm.