talismon - 6:54 pm on Feb 14, 2011 (gmt 0)
I'd say it's MANUAL analysis versus algorithms.
This is an important point, particularly with JCP. After they clean up and the penalty is MANUALLY lifted they come back and they will still partially reap the benefits of their paid link strategy, here's why:
Let's say they have 20k paid links from different networks. They are able to remove 80% of them (they couldn't get in touch with the other 20%). Google is not going to go and manually devalue those 4k links. A portion of those links will still count for them.
I saw this a few years ago with a site that had embedded links in a widget. Banned for one year, clean up and now they are dominating the results again. It's not all b/c of those spammy legacy links but they are certainly still helping.