indyank - 5:49 pm on Apr 18, 2011 (gmt 0) [edited by: indyank at 5:53 pm (utc) on Apr 18, 2011]
i have 2 theories for this (based on whatever I observed)
1) Lots of quality links do seem to save the page from loosing out in the SERPS. I think the quality algo works by discounting the links.When you have strong backlinks the quality discount may not be strong enough to have any impact on the page in SERPS.
2) Panda picks a set of pages and works on them.It might be that this page wasn't included.
Many of these lead me to believe that this is a very intensive process and google may not run this often.
[edited by: indyank at 5:53 pm (utc) on Apr 18, 2011]