Why are there significant changes in the amount of duplicate content without any known action?

[allurez]

I've noticed a surprisingly rapid change in duplicate content over the past month. I'd noticed ~6,000 instances of duplicate content, after disavowing bad links we went down to 3k, this makes perfect sense to me. But after that, without doing anything whatsoever, from last Thursday, the 20th, to yesterday the instances of duplicate content decreased again down to 2k. Could this just be a delayed indexing of pages or are there other factors here? Thanks for the help.

[allurez]

Come to think of it, the only thing we did do was fire the SEO company that we had working for us, and started doing SEO in house, but this doesn't make sense in terms of rapid shifts in duplicate content.

[Andy.Drinkwater]

Without really being involved, it is very hard to try and figure this out exactly.

For now, I wouldn't worry unless you start to see problems, such as a drop in the number of pages actually indexed, drop in traffic or searches where you appear.

-Andy

[allurez]

To the best of my knowledge we've changed nothing about our site recently which is why I'm trying to attribute this rapid drop to something and the only thing we've done is disavow the links. So the disavow was just a shot in the dark to try to understand these changes.

[KevinBudzynski]

Are you using any parameters (tracking/session id's) on your site?  Also, what Andy said--disavowing wouldn't decrease this #. It was something else.

[Andy.Drinkwater]

You can get problems with duplicate content from all over the web, but a disavow would have absolutely no impact on this. That is to distance you from external links that you don't wish to be associated with.

As this is a something related to the MOZ products, I can't give you an answer on that I'm afraid.

Have you made no actual changes to the site that could account for this? If you can, re-categorise this post to include Product Support.

-Andy

[iSTORM-New-Media]

Can you look at your crawl diagnostics and see the difference in how many pages were crawled at each of those intervals? That would help diagnose what's happening here.

Thanks

[allurez]

I was under the impression that duplicate content can not only be caused by duplicate content on the site but actually also from outside sites, even notable ones, using directly duplicate content. http://moz.com/blog/duplicate-content-in-a-post-panda-world

See below:

(3) Cross-domain Duplicates

A cross-domain duplicate occurs when two websites share the same piece of content:

These duplicates could be either “true” or “near” duplicates. Contrary to what some people believe, cross-domain duplicates can be a problem even for legitimate, syndicated content.

Anyway, we're using Moz's dashboard to give us insights into duplicate content.

[Andy.Drinkwater]

Hi,

First of all, disavowing will have nothing to do with the number of duplication warnings you get. This can only affect inbound links and even then, you won't see any drop in these through Webmaster Tools.

What are you using to see the duplicate pages?

-Andy