underglass - 12:03 am on May 12, 2011 (gmt 0)
As what has moved up in many long tail searches are home pages.
I've seen this on my site and I was not hit too hard by the Panda updates.
Pre-Panda, I noticed that when I did an internal navigation change (major site change), Google would replace the ranking internal pages with the homepage. Then after a trial period, the internal page returned.
I am wondering if one of the effects of Panda is that Google is replacing internal pages with home pages as it re-assesses the value of the internal page.