Very often, display advertising stands at the beginning of the customer’s journey, and with this type of ad you can target a much broader audience during the inspiration/awareness phase and create attention for your brand thanks to targeted placement. It is also one of the cheapest ways to increase brand awareness. Just going off of the Google Display Network alone (which SEMrush provides data on), it reaches approximately 92 percent of all internet user and 65 percent of those users are reached daily.
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.
Google makes constant efforts to improve the search algorithm and detect quality content and that is why it rolled out the Google Panda 4.0 update. What is this update really doing? It deranks low quality content and boosts the high quality one, according to Google’s idea of valuable content. In the screenshot below you can see what kind of content you shouldn’t be looking into if you are really determined in making a mess out of your organic traffic.
Well, yes and no. Sure, you can get hit with an algorithm change or penalty that destroys all your traffic. However, if you have good people who know what they are doing, this is not likely to happen, and if it does, it is easy (in most cases) to get your visits back. Panda and Penguin are another story, but if you get hit by those it is typically not accidental.
Secure (https) to non-secure sites (http): Since Google began emphasizing the importance of having a secure site, more websites are securely hosted, as indicated by the “https” in their URLs. Per the security protocol, however, any traffic going from a secure site to a non-secure site will not pass referral information. For this issue, you can correct by updating your site to be secure through a third-party SSL certificate.