I think this is something that could be very helpful/informative for others. I have not found any information about this as a result of my searches. I've posted once or twice in the past few weeks as I've been trying to understand what has been happening with the site.
Our main "issue" is how to properly transfer from two mirrored sites to one. Google was fine with our two mirrored sites - and primarily showed results from our "oldest" domain (which makes sense). However, we know that Google prefers SINGLE sites with unique content.
Our domain names were:
So, we took our oldest domain (which also has a hyphen in it) and put a 301 permanent redirect on it to point at our newer domain name. We have a mixture of backlinks - some sites point to our new domain, others to our old. DMOZ lists our new domain.
When we used to do a "backlink" search on Google, it would show results for both our domains (in other words, Google knew we had mirrored content and DIDN'T penalize it).
After making the change, on October 9th (with the update) our Company-Name.com results completely disappeared from the index. We had a few results that were showing for CompanyName.com - but all of those subpages disappeared over the next few weeks.
Soon, only our index page on the new domain was showing up in the results. AND THE CRAZY THING is this: there IS a penalty or filter of some type being applied to our newer domain. When we search for our Company Name, our site is #3 (#1 is a another site this company has, #2 is a nonsense result that has some rock band mentioned in a news article, #3 is us).
NOT ONLY THAT, but when we click the result to visit our page, the PR bar is grayed out. When we simply type in our URL to visit the site, we show PR 5. Consistently and repeatedly, anytime we click through from Google to our home page, the PR is greyed out. Otherwise, we show PR5. That tells me something is being filtered or penalized with Google click-throughs.
Several days ago during the update, I did some searches on -IN and found we were scoring #1 for our Company Name - and the gray penalty bar WASN'T showing up when we clicked through.
Now, it's back to the way it was.
I would be thrilled if GoogleGuy (or anyone else) could offer some good information on how to properly transition from mirrored domains to a single domain name and what happens in Google. As it is, if this keeps up, we'll have to revert to mirrored domains (which we DON'T want to do - we're happy with ONE URL and know that Google prefers that as well).
Is there some type of quasi-penalty that is applied to mirrored sites so they don't show up (I believe there is)?
How long does it take Google to remove that quasi-penalty?
Google VERY quickly dropped our old domain when we put the 301 on it, but why hasn't Google figured out our new site?
Also, Googlebot appears to only be visiting our main page and not crawling the site (like it used to). Is that because of this transition and quasi-penalty on the new site? Maybe Googlebot still thinks “CompanyName.com” is a mirror of our old domain (Company-Name.com).