Today, the list of questions on the main page suddenly started looking differently. This morning, all questions had the same background. Now, some of them have a greenish background.
It looks like a feature to me. However, I can't figure what the green ones have in common. Also, I didn't reach any special reputation number or flag weight today. So I don't know what it accomplishes, or why it could have been turned on.
I don't mind it, but I am curious. What it is, and why is it there?
This is due to a Stack Exchange feature I've never particularly liked; if you don't ever specify any favourite tags, it chooses one or more "frequented tags" for you and that's what the colouring means.
In this case, all of the highlighted questions are tagged cheese, so I guess you've been looking at a lot of cheese-related questions lately (who hasn't?).
You can stop this from happening by setting up at least one favourite tag. It doesn't have to be a real tag, if you don't want to see any highlighting. Here's what mine looks like (this is at the top right corner of the front page):
