Last week, Google told us they pushed out a completely rewritten algorithm named Hummingbird.
They said the new algorithm was released a month or so ago and no one should have noticed it. But as I said, I think we did notice something. Why do I think that?
On 9/12, 9/4 and 8/24 we saw significant chatter in the forum to warrant us asking Google if there was an update. Google denied that there was an algorithm update all times. But all of these may correspond to a possible overlap with Hummingbird.
I cannot tell you if all of them are Hummingbird related or if none of them are. Only Google can tell you that.
All I can say is that on those dates, we saw complaints about ranking shifts. Google denied that they were anything. A month or so later, Google announces there was an algorithm update that completely rewrote the Google algorithm, it should have no visual impact on rankings and no one noticed anything. No one noticed anything? Really?
Again, I have no way to know when you may have noticed an update that was specific to Hummingbird. I suspect parts of Hummingbird has rolled out slowly over time, even before a month ago. But on which dates? Only Google knows. Do they correspond with 9/12, 9/4 and 8/24 - no idea.
So how do you know if the Google Hummingbird Algorithm hurt or improved your site in Google? You don't and will never know, without Google confirming the roll out dates of Hummingbird and also confirming nothing else launched on those dates that were related to ranking.
Forum discussion at WebmasterWorld.
I intentionally made this hummingbird into a mockingbird by making it into an annoying animated GIF, as per the chatter in the forums.