I am seeing some early signs of a possible major Google update currently underway. The chatter has definitely spiked in the early morning hours of today, September 4th.
This comes shortly after an unconfirmed August 21st update. In fact, that update post has well over 250 comments and a bunch of recent ones this morning reporting the update people are seeing this morning.
One WebmasterWorld member said:
Yes we are seeing same in several high traffic sites, about 50% decrease at exactly same time, must be going something very big.
Another preferred member said:
Yep 25% drop here since Thursday 29 Aug. No WMT messages, no idea why. All I can see is that Google has turned up the preference for brands.
Via the comments in our August post:
30% drop in traffic on Aug 24. Another 80% drop in traffic on September 3rd. Google analytics landscape (graph) changed from Mountains to Rivers.
Via one of the threads at Google Webmaster Help forums:
We've noticed this morning that the site's rankings dropped significantly (about 80%). I've checked the manual actions in WMT for a penalty, nothing, I've searched for a major Google Algo update...nothing. I have no idea what's going one, especially that this site is 7 years old, the traffic before this major drop was about between 20k and 30k daily visitors. We've done 0 link spamming and the only thing I found wrong so far is that some spam websites copied our content in full. We've did several DMCA reports on that but that shouldn't be the problem of this major drop. We have no clue what to do.
Something major is going on and I'll see if I can get a comment before I go offline tonight.
Update: Google has nothing to announce. I am sorry.