Love the five different area of investigation that you went over, great way to analyze and diagnosis the issue. I would also definitely agree doing a rankings comparison between the two time frames, and not only check what your Google ranking is, but also track the search volume for your keywords to see if it has fluctuated or gone down. Google Trends is a great tool for this as well, as one of your keywords that your ranking for may have just lost popularity online.
You are giving some great advice to use for increasing readership and loyal followers. I am trying to include 2-3 sources from each of your list categories so that I have a balanced approach to increasing traffic. Right now I am learning Stumble Upon and Squido.com. Although I submit articles to Ezine, I think my keywords are not strong enough to get a good click through rate. I am getting better about writing articles with strong keywords now; sort of fell off the pace of that when I started using a lot of guest authors :( Thanks for your great insights and check list for increasing traffic, Brankica!
Organic Search is visitors who reach you by Googling or using another search engine which Google recognizes as a real search engine — mostly Bing and its second string, Yahoo. People using other search engines like DuckDuckGo or sites which are now commonly used as search engines but which have other purposes, like Pinterest, will show up in Referral traffic and in the case of Pinterest, in Social. If you have a good, well-optimized website, Organic Search will usually be your most frequent source. At our lab site, we do nothing to encourage other sources, so Organic Search is absolutely the top.
Beyond organic and direct traffic, you must understand the difference between all of your traffic sources and how traffic is classified. Most web analytics platforms, like Google Analytics, utilize an algorithm and flow chart based on the referring website or parameters set within the URL that determine the source of traffic. Here is a breakdown of all sources: