Our site got hit by Panda, pretty much sitewide. However, we've got a forum hosted within the same domain. The forum URLs were the only URLs NOT to be effected. Go figure!
Uber_SEO, that is very true. I know for sure that the panda bot was explicitly looking for forums on my site.Immediately after being pandalized I saw my GWT reporting 404s for [site.com...] from several of my navigational pages.
Probably, they didn't want to touch them.
It is not just the forums but I also believe that Google platforms including Blogger were untouched by panda.