While checking my question's history (for the first time as I remember), I clicked the tiny clock like symbol beside the vote signs on my question and saw
16 hours ago history became hot network question
I don't understand what that means. Then I went around checking some other questions, most of them had the same thing in their history. Like this question, this and this. Some questions show this while some don't. I also checked most of my questions on English Language and Usage, they also have "became hot network question". What does it mean?