TheMadScientist - 10:30 pm on Feb 12, 2010 (gmt 0)

The algo changes throughout time, so if they used to use keywords (more specifically keyword density) as an indication of topicality and people keyword stuffed they would reasonably and rationally have to 'filter' results appearing to be 'stuffed' in an effort to take advantage of the algo, but if they moved beyond simple keyword usage and got further into processing the English language, say by moving to a phrase based topicality model, they would eliminate the need to base rankings on keywords and at the same time eliminate the need to 'filter' or 'penalize' for stuffing, because site owners could no longer take advantage of the algo by using the technique.

IOW: If you eliminate the need to base rankings on a certain variable, you also eliminate the need to 'filter' or 'penalize' sites (pages) based on misguided attempts to influence rankings based on the variable eliminated, because it no longer works in either direction...