Dan Rampton from Yahoo Search said:
We’ll be rolling out some changes to our crawling, indexing and ranking algorithms over the next few days and expect the update will be completed soon. As you know, throughout this process you may see some ranking changes and page shuffling in the index.
I checked the forums this morning and found no new discussion around Yahoo Search. This implies to me that the update is over and I doubt we will see another update until the end of this month. I may be wrong, so keep an eye out on your Yahoo referrals and rankings.