A typical page from my forum (besides the commercial website) that google might take a "thin content" is this:
Simple question, simple answer and to the point.
Yeap, a perfect example of what could be considered thin content. I am in agreement with you it's short and to the point and should be useful to a human, however, we are not dealing with a human here. Its a computer algorithm, Despite its complexity it is still pretty dumb when handling pages such as this.
Normally the trick is to add extra content which I appreciate is difficult. One technique we use here as this is a very similar type of site is to show related posts. This keeps the pages unique but pads out the content. It also has the benefit of generating more internal linking to relevant pages, lifting the importance of each page in the list. Ours is done automatically and not sure how difficult it would be for you to achieve something along the same lines, but it something I would possibly add.
ok, I just did exactly this, 10 related questions/links to the same forum.
I used to have it in the past, dont remember how this feature became deactivated. Maybe I did it by accident, maybe I decided to clean up the page. We'll see. If this works, Thank you for the tip!
I just noticed, the SAME decline, for the same dates happened for the mobile usability. Is this also due to "thin content"?
Google uses the mobile version of your site to drive search console. So I would expect to see the decline there as well.
15 days have passed since I added the "similar pages" feature. The number of QA and Mobile pages did not go up.
The google rankings have recovered to ALMOST the previous level, like Matt had suggested.