I don't usually take much notice of these (unless I click on one by accident because my mouse has 'drifted'). But sometimes they seem so random!
I just had one that had a picture of cattle on and a logo asking me if I'd considered the 'feed gap'. I was vaguely intrigued and clicked on it. It was for cattle feed (I have no cows and don't live on a farm), telling me to check that my cows could reach their forage through the feed bars. I have absolutely no idea what has triggered that ad to appear.
Anyone else got a random (and slightly bizarre) ad appear?