Duplicate content due to parked domains

[ajiabs]

I have a main ecommerce website with unique content and decent back links. I had few domains parked on the main website as well specific product pages. These domains had some type in traffic. Some where exact product names.  So main main website www.maindomain.com had domain1.com , domain2.com parked on it. Also had domian3.com parked on www.maindomain.com/product1. This caused lot of duplicate content issues.

12 months back, all the parked domains were changed to 301 redirects. I also added all the domains to google webmaster tools. Then removed main directory from google index. Now realize few of the additional domains are indexed and causing duplicate content. My question is what other steps can I take to avoid the duplicate content for my my website

1. Provide change of address in Google search console. Is there any downside in providing change of address pointing to a website? Also domains pointing to a specific url , cannot provide change of address

2. Provide a remove page from google index request in Google search console. It is temporary and last 6 months. Even if the pages are removed from Google index, would google still see them duplicates?

3. Ask google to fetch each url under other domains and submit to google index. This would hopefully remove the urls under domain1.com and doamin2.com eventually due to 301 redirects.

4. Add canonical urls for all pages in the main site. so google will eventually remove content from doman1 and domain2.com due to canonical links. This wil take time for google to update their index

5. Point these domains elsewhere to remove duplicate contents eventually. But it will take time for google to update their index with new non duplicate content.

Which of these options are best best to my issue and which ones are potentially dangerous? I would rather not to point these domains elsewhere.

Any feedback would be greatly appreciated.

[Dr-Pete]

Oh, wow - if you're talking a couple of years ago and major ranking drops, then definitely get aggressive. Remove as many as possible and Robots No-index them. If you've got the Robots.txt directives in place, Google shouldn't put them back (although, from past experience, I realize "shouldn't" isn't a guarantee). If you're down 90%, you've got very little to lose and clearly Google didn't like something about that set-up.

Unfortunately, that's about the most drastic, reasonable option. The next step would be to start over with a fresh domain and kill all of the old domains. That could be a lot more hazardous, though.

[ajiabs]

Thank you Dr. Peter.

Couple of years ago my search engine positions tanked by around 90% and have not picked up back yet. At that time assumed it was due to the duplicate content on these domains, as they were parked ( Not 301, just domain masking) at that point. To avoid that duplicate content problem I moved to 301 redirection.  None of these domains have any link juice to speak. Some domains have some typein traffic. I was just trying to capture them rather than link jiuice.

I did de-index most of the domains from webmaster tools in the past. But Google put them back, after 90 days or so. 301 redirection in place did not help that much.

If Google thinks there is a chance of abuse of the 301 of new domains, I would start removing the new domains completely and point else where so that Google can have some new content.
Thank youAji Abraham

[Dr-Pete]

Ugh... 75 is a chunk. The problem is that Google isn't a huge fan of 301-redirecting a bunch of new domains, because it's been too often abused in the past by people buying up domains with history and trying to consolidate PageRank. So, it's possible that (1) they're suspicious of these domains, or (2) they're just not crawling/caching them in a timely manner, since they used to be parked.

Personally, unless there's any link value at all to these, I'd consider completely de-indexing the duplicate domains - at this point that probably does mean removal in Google Search Console and adding Robots.txt (which might be a prerequisite of removal, but I can't recall).

Otherwise, your only real option is just to give the 301-redirects time. It may be a non-issue, and Google is just taking its time. Ultimately, the question is whether these are somehow harming the parent site. If Google is just indexing a few pages but you're not being harmed, I might leave it alone and let the 301s do their work over time. I checked some headers, and they seem to be set up properly.

If you're seeing harm or the wrong domains being returned in search, and if no one is linking to those other domains, then I'd probably be more aggressive and go for all-out removal.

[ajiabs]

Hello Dr.Peter

Thank you for helping out.

There are around 75 or so domains pointing to the main website. When they were parked (prior to November 2014) on the main site, they were added as additional domains, which were url masked. So at least 30 domains were indexed in google with same content as main content.

12 months back, I realized the duplicate content error and changed the domain parking to 301 redirects. Also used ‘remove url’ functionality in Google Webmaster tools. Even after 12 months, I noticed a number of domains had duplicate contents in google index.  
This I removed the pages from the addon domains again using google webmaster tools.

To give you an idea my main site with original content/links is iscripts.com and an addon domain socialappster.com is pointed to a product page at iscripts.com/socialware. If you do a site: socialappster.com in google you find few pages in google index, even though it is 301 redirect for more than 12 months now. Similar issue with other domains pointing to product pages as well as whole site.

Appreciate any direction you can provide to clean this mess.

Thanks

Aji Abraham

[Dr-Pete]

Oh, and how many domains are we talking (ballpark)?

[Dr-Pete]

What was happening when they were parked - were they 302-redirected or was it some kind of straight CNAME situation where, theoretically, Google shouldn't have even seen the parked domains? Trick, of course, is that Google is a registrar, so they can see a lot that isn't necessarily public or crawlable.

Did the additional domains get indexed while parked, or after you went to 301-redirects?