Some time back we reported that Yahoo! Update Of Search Index Bags Unfriendly Responses. A recent comment to the Webmaster World thread on Yahoo! Search update suggests that Yahoo! is undoing the update to the way it previously was.
One comment states
Seeing some rollbacks…anyone else?
Another comment says:
I wouldn't call it a rollback, but 2 of our terms have been "re-indexed" or equivalent, and we have alas lost our #1 position for one and slipped to the second page in the other. I figured this would happen eventually.
It seems to be pretty confusing for everyone. Whenever these is a change or update, Yahoo! does not care to clarify. However, it is pretty evidential that changes are taking place in Yahoo! Search Index.