They should probably label this update the "Do Nothing" update for the fact that it didn't do much more than clean up the index. Which is definately good, and in most cases better than the latter, but I think it kinda had a lot of people's hopes up for something a lot worse. Which seems to be a result of past updates from other unmentioned search engines that have us shell shocked a bit. To Yahoo though, we can say they are kinder creature this time around. I have been following a lot of the forums this morning on the results from the update. Many people not really seeing any changes whatsoever as a result of the changes. One member on SEW even labeled it a clever farce, or maybe an early summer joke.
What does seem to be happening is characteristic of how Yahoo handles sites low quality sites in the top results. They consequently don't ban them, they just knock those top sites down a page or two. I have read about 4 reports today of people claiming to have the #1 position for a term and then consequently getting slapped down to the 2nd, 3rd, or 4th page. Some may disappear completely. Once at the #1 spot its not necessarily smooth sailing on open waters, so don't get too comfortable. Barry posted on SEW that he think "They didn't say anything about a new algorithm. Just improved index, which implies more sites in the big Yahoo Search database." Sounds close to me.
Check out some of the other forums discussing the Do Nothing Update