Could changing PageRank cause the number of pages indexed and SERPs positions to fluctuate?

Assuming no on-site changes and also assuming no significant changes in competing pages, is it possible that some pages could go totally missing from SERPs and others seeming to drop out of site all the way back to the last page when nothing appears to have changed?

Matt Cutts, in the same Infrastructure Status update said as much when he wrote,

“If you used to have pages in our main web index and now they’re in the Supplemental results, a good hypothesis is that we might not be counting links to your pages with the same weight as we have in the past.”

Beyond that, if PageRank can influence which index a given page is in, Main or Supplemental or whether it is even indexed at all, if a given page's PageRank were to decrease for some reason either as Matt mentioned or even one or more inbound links no longer existing, it would not be too hard to imagine the page moving from the Main Index to the Supplemental Index or dropping out of the index altogether.

Read also this forum with topic: What more could I do to improve my SERP?

fullnotes: cass-hacks.com

Google is a forgiving friend:

I see this sort of thing over and over :

don’t do this, don’t do that Google will penalize you.

For the most part this is not true, Google does not penalize your site for anything other than what is on the site.

For instance, if you spam on forums, or use auto submit tools. Google will not penalise you for theses things, but instead will disregard a high percentage of those links. If its not possible for a human editor to add this number of links in a small time, or there is an unlikely pattern of link balancing.. It’s easy to detect.

Google will not negatively mark you for these, you will not have a lower PR or SERP result due to these, otherwise what would stop your competitors from doing this to your site. There are a couple of sites that I would love Google to penalise, but thankfully its not in my power to do so.

You will get penalise for what is on your site...
- don’t link out to link farms, this will harm you
- don’t get paid for linking to sites if you are not using nofollow, this once again may harm you
- be careful who you do link to, relevance is utmost important
- don’t use black hat techniques (hidden text, too high keyword density)
These are place where you may get penalise - all thing that ONLY the site editor has control over.

If you have found that you have used any of the methods above, and have been penalised. As originally stated, Google is forgiving. Let them know that you have made the changes, and will not use any of the techniques in future... and make sure you don’t use them ever again!

Article by. mpea
Fullnotes: http://talk.iwebtool.com