On January 19th we reported a Yahoo! Search Update was underway. Now, recent updates to that WebmasterWorld thread suggest that Yahoo! is rolling back that update, to the previous state.
On February 14, starting at message number 3252410, textex asked:
Seeing some rollbacks...anyone else?
Some are not considering this a rollback but a phase two of the update.
Exactly what is going on, I am not sure. I do not think this is a full new algorithm or index update. But there are substantial reports of changes taking place at Yahoo!
Forum discussion at WebmasterWorld.