I’ve already talked about index updates some in the past. These days rather than having a large monolithic update, Google tends to have smaller (and more frequent) individual launches. So I think my Sept. 8th, 2005 post on the subject of non-updates was just mentioning that some new backlinks were visible, but not much in the way of algorithms/scoring/metadata had changed. After that, some people might have noticed some changes around Sept. 22, 2005. Or some CJK folks might have noticed some changes around Oct. 5, 2005. Or a few European folks might have noticed some changes around Oct. 7, 2005. Or some people might have noticed some changes this past weekend.
My point is that more than ever, we are constantly working to improve our algorithms and scoring. Some changes are hardly noticed at all. Some changes (e.g. user interface improvements) are more visible. Some changes have nothing to do with spam, such as the changes for Chinese and Europe that I mentioned above. Some changes do try to decrease spam or increase core quality.
Just to give you a heads-up, I think a new set of backlinks (and possibly PageRank) will probably be visible relatively soon; I’m guessing within the next few days. I still expect some flux after that though, just to let you know.
Update: Just to clarify, these days with lots of smaller and larger changes happening at different points in time, it’s a little arbitrary to decide when to call something an update. That decision has usually fallen on Brett Tabke’s shoulders over at WebmasterWorld (WMW also chooses what name they want to call it when Brett decides enough has changed to call it an update.) Given that there should be new PageRank/backlinks visible in a few days (assuming no issues at our end), I wouldn’t be surprised if Brett slaps a name on it pre-emptively, even though there will still be some flux to come.