Part two of the WebmasterWorld thread on the July 2008 Google update discussion is virtually all about how Google is yo-yoing the results. Meaning, one day a site can have top positions for a keyword phrase in Google, the next day it would drop off and then it would come back. This yo-yoing continues to cycle back and forth according to many many webmasters.
WebmasterWorld administrator, tedster, has confirmed the issues himself:
The most perplexing new SERP observations are those that report cycling, sine waves, yo-yo, rollercoaster, or pick your favorite synonym. Sometimes these cycles happen down in the deep results pages after a url has dropped from page 1 - an apparent penalty. And sometimes the cycling appears on page one - from 3 to 10 to 3 to 10, day after day or week after week.
I don't have a site under my auspices that is showing this effect, but I've been asked to look at few that are - and so far, I can say that the phenomenon is real, but am mystified by it. I felt this way when the -950 first appeared back in 2006 or so, and slowly some understanding of that has emerged. Sure hope we can get some understanding about the yo-yo phenomenon, too.
Scanning through the reports myself, all show that this is more than the typical complaints you see from webmasters and SEOs on Google's fluctuations. It seems to be more extreme and more frequent then in the past. Tedster coins it well:
That name we use - organic rankings - is proving to be more and more accurate.
This leads me back to why I purchased Yo-Yos as schwag for the Search Engine Roundtable. I said back in early 2005, "Since the SEO world is filled with such ups and downs, we thought it would be clever to give out yo-yos. Then we added the glowing aspect to the yo-yo to make it "pulse" a bit." That still applies today, but it seems even more so. Heck, if you want a free Yahoo, send me a 6"x9" cushioned envelop with postage and your mailing address on it and I'll send you one. You can mail it to my office, attention Barry Schwartz.
Forum discussion at WebmasterWorld.