I just noticed that in the "Questions" view, I see some questions with a blue background, e.g., the first one here:
Is this some new feature?
On the other hand, ignored tags makes questions labeled with them to appear with less visibility (shadowed?).
+1 to @AndreSilva. Specifically, on the right side of the screen / screenshot under the blue box you see "Favorite Tags". Yours include r time-series forecasting. Questions with those tags will be highlighted for you on most CV pages (if you go to the tag's page, it wouldn't be). In your example, the highlighted thread is tagged with
[time-series]. Favorite Tags are added automatically by SE based on your pattern of answering questions. If you don't want those threads highlighted, click the "edit" link next to Favorite Tags and add some nonsense (I have