mslina2002 - 11:14 pm on Jun 22, 2011 (gmt 0)
My site is not as large as yours but I have deindexed about 3000 pages (80% of my site) of affiliate product pages and seen a rebound of traffic in Panda 2.2 (86% of prePanda). Before doing this however, I was able to identify prePanda that these pages were not drawing in hardly any traffic, were dupe or were blank - from WMT.
Often with large datafeed sites I look at:
(1) Dupe content due to parameter handling, search or query. Look at WMT parameter handling to solve this. Noindex search queries.
(2) Often times these dynamically created queries produce lots of blank pages. Identify and no index these.
(3) Look in WMT to identify pages that have been penalized. I have found many to be these datafeed pages. I looked at pages prePanda and postPanda.
I am working on adding back some product feed pages selectively and content to get back the prePanda level traffic since I am left with only 20% of the site.