Reports Of Another Google Update : September 4th
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.
This amazing conversation on this article should answer some of your questions: here