incrediBILL - 3:53 am on Jul 1, 2010 (gmt 0)
MOST PEOPLE DON'T KNOW HOW TO PAGERANK SCULPT PROPERLY
Googlebot has screwed up more than a few sites I know about that appeared to do everything right but it went south in the index and this wasn't just recent, it's happened since rel=nofollow first started best I can remember.
People that knew what they were doing could sculpt a site without using rel=nofollow in the first place, it was just a placebo for those that couldn't think it through and it confused Googlebot in the end.
Besides, the real elephant in the room was that Google couldn't tell external link relevance so they built this contrivance so you could tell them those links weren't important.
I always said if Google couldn't tell that Granny's Crochet Blog wouldn't normally link out to pharma spam then the Emperor had no RELEVANT Clothes which is why they made rel=nofollow in the first place.