I'm trying to create a big main site and many sister sites. They all will be hosted in a same server, but will be multiple domains.
When a sister site posts an article, it is submitted to the main site. For example, if the sister site posts an article
sistersite.com/article/seo-optimization, the main site will have immediately a new article page
mainsite.com/article/seo-optimization. This can definitely lead duplicate contents across different domains.
I have known that the search engines don't like the duplicate contents. The main site may have SEO penalties because of those duplicate contents. I want the main site winning over the sister sites in terms of SERP ranking. I'm thinking the following options:
noindex, followfor the sister sites
- Adding a canonical URL
mainsite.com/article/seo-optimizationin that page of the sister site.
- Updating the content by a moderator for the main site before publishing once it receives a new article.
All of these have some pitfalls:
- May all of the sister sites not be listed in SERP because of
noindex? I want them listed somehow in SERP.
- Is it really a valid canonical URL if it is referring to another domain? In fact, I don't want the main site URL included in the source code of the sister sites.
- It will have work-overloads for the moderator because there may be many articles submtting a day. And how does Google decide what are duplicate contents? For example, 80% of the contents is same, 90% of the contents is same, etc.
What would be a best solution to solve duplicate contents over different domains?