zachary - 6:15 pm on Oct 1, 2012 (gmt 0)
I think the updates already been over, and there is still no announcement from Google's side. They will come up with a announcement that they are really happy with the update and how it has came up.
I will tell you the full story, and i assume this is the reason for this update. Most of the people might not agree with me, but i believe this is the only reason.
This month in the start bing launched a campaign called bingiton and most of the people started noticing bing. Search Market share of Bing was going up in September and Google have to launch this update so that its search share increases.
Obviously when they launch a new update which doesn't make sense and quality sites go down, ppl search more on Google pages, where their site have gone and search market share of Google goes up.
You will soon see the search share will come out of for September and Google will be on the same numbers as it was in the last month.