Dropping in organic traffic

Selected answers from the Dumb SEO Questions Facebook & G+ community.

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  Vangelis Kovaios: Hi all,
  After September 2014, a website i collaborate with (wordlesstech.com), has started dropping in organic traffic between 30-50% in YoY comparison (http://screencast.com/t/pGx6uTIhvsre) and this drop continues until today.
  I have checked at webmaster tools and there are no indications of manual actions.
  During that time range ; (October 2014) Google rolled out several updates such as Panda 4.1, Google News and Penguin 3.
  Could you help me diagnose if the website got hit by any of these updates, and if not, what else could be the reason for this drop?
  Thank you in advance,
• 
  Vangelis Kovaios: Hi Tim and Jim, Thank you both for your explanations. I will apply the rel=prev/next tag the soonest to solve the duplication issue. Regarding the Barracuda Panguin tool, which Tim suggested, i have synced the analytics account, but i can`t really tell which of the updates could have hit the website... (http://screencast.com/t/HSDwTPLu) Also, all texts in blog posts are not exact copies, but summaries from other sources and there is always citation (with hyperlink) at the end of each post. As for the link profile of the website, i haven`t done any link building, apart from sharing most of the blog posts in social media. The site (wordlesstech.com) has grown only because of its frequently updated content. Therefore my question is, could a "self-triggered" Panda filter have caused this drop?(http://screencast.com/t/GiVOY0Vzg) Apologies for bringing this topic back to the table but it critical for me to solve it. Thanks in advance,
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  Vangelis Kovaios: PS:I` ve also noindexed all "tag" pages according to your recommendation.